Inspection of a 904 torqueflite

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Years ago.....when I was in my early teens. I got ahold of a non running car that no one wanted.

I knew nothing about it. I had no one to teach me anything about it. When I blew up the engine by running it low on oil. The people who knew what was happening just laughed as they watched. After the fact. They told me what I did. I’ve built several engines since. Not one of them has blown up. I still remember them laughing and the correction after the fact.

The deal is. I don’t know how to do this. It’s my first time. If I blow this transmission to the moon. If it ends up in outer space....or in the trash can. That just is what it is.
I’ll figure out my stupidity or my lessons. Then go get another one and do it again.

So......yes I spent an hour checking clearances.
Because I want the experience. Now I know off the top of my head what each one should run and what they are all called. What they all do and how each washer fits into the equation. This whole inner workings of this this are a complicated process. There are things I don’t know. I know the governor controls shift points. I don’t know how yet. They say a ten year old girl could do this. I want to meet one. Is it simple.....yeah. But is it simple to modify it. Not really.

Is the reverse band flaking.....a little bit. I’ve already decided to replace it......I did scratch it to see how brittle it was. It wasn’t bad. Both drums have no hot spots on them and lots of friction left....the question is.....what shape is that friction material in?

Standing the trans on the output shaft. It reads .040
Not standing it on there....it reads .050

The Manual doesn’t say to stand it up on the output shaft. So I didn’t take that reading into account. However....to satisfy both people without getting mad at me. I did both. Both readings are within the factory spec so I knew it was ok.

Your one of the only ones even giving advice.....it’s valued. Even if it’s beating me up a little. I don’t care. It’s welcomed. Learning is a messy process when your dealing with older worn out stuff and you don’t have a good base on what it was like new and have never seen one before.

I have seen some of the experts say to stand it on its end. Since I don’t know....and I don’t know why.....they do this and others don’t. What do I have....realistically? Think about it. I really don’t know.
I think that way because I’m in the medical field and in that environment. You cannot be wrong. You have to know.....and you have to be sure. Which is why I know by the time this goes back together it will work well.....all these measurements to me are like a set of 50 medical lab value measurements telling me what’s wrong with someone and why. Then how to fix them

If I toss the idea around about using parts that are older. It’s because I don’t know how much life is left in them. Hell....I can’t exactly measure a reverse band. I see that it’s super thick....intact and has 99% of its surface area. I see a perfect drum with no hot spots. So how can I possibly know if it’s good or bad. It’s been in there 45 years and still looks almost like it was just put in there.
So how could I know. It might be a total waste of money buying a new one. Since I budget this and I’ve blown this years already....I can’t exactly go back. The experts would know whether to replace it or run it.....I don’t and I do t exactly have a way to know except look on here where several are saying that the reverse band never wears out. So they don’t replace it.

I probably annoy the experts. However.....I’m very good at what I do because I ask the questions that are advanced and basic so I have complete understanding.

I have to replace the parts based on ignorance. Based on lack of experience. I don’t think too much....I’m not over complicating this. I’m getting information to make sure the patient survives..... it it’s just a transmission and can be replaced. It’s not a human so there is room for mistakes......but I still think this way. I can’t turn it off just because I’m not at the hospital.

If the experts want to watch me blow this thing up. I’m fine with that. Of course I don’t want that. I’ve looked at every post I can find about them talking and even arguing about this stuff. I have to sort through all the info of them talking about it.

Many times they talk to people like those people know and have the same expertise they do. When my friend wi5out kids asked why my 7 year daughter was asking so many questions about how to play the simple game of battleship. I simply told him that she’s 7 and knows nothing. She’s not in her thirties. She really just doesn’t know and he forgot that someone could not know something so simple. I’m like that with transmissions. Hell....I’m not even a novice.


So....after my stupid rant.

What makes me think that’s a low gearset is the stepped sun shell. There is only one that looks like that. Of course I would confirm that before buying it. I would even ask him to measure it some. He has the front planet turned the wrong way so I can’t see it. That particular planet from that side looks like the one in the older style . The other sun shell with the front and rear sun are the same. That’s the one I have.
What I don’t know is about that stepped sun shell yet. I don’t know the spec and as I have seen several people sell them as bolt in high performance parts....I’ve seen where lots of people run them. They don’t talk about them as far as matching parts. They talk of 5 drum clutches and beveled pumps....they talk about machining pistons and adding clutches to 4 drum....they talk about the 999. They don’t go into do these things work individually. There is a lack of detail in the information. They do all kinds of mods at once. For me....I think 4 clutches are fine. You also have to remember. It didn’t make sense that I even had 4 clutches a few weeks ago. Now I know they do and why. Bigger cars needed them and Chrysler could not afford to redesign the transmission. Which is also why they put lower gears in there. To keep the highway rpm down but give the bigger 70s cars good take off. They could not afford to make an overdrive transmission so they went cheap and did this.

I now know an overdrive 518 won’t fit without going through hell. I also know now that I can’t convert this to a lock up clutch.

If I put this transmission together right now. With all the same parts. It’s going to run fine. It came out running with no apparent defects. Which means if I just add a few parts to tighten it up and keep close track of the adjustments it should work just fine. There are always variables The would show otherwise so I can’t say that 100%that it will work. I’m not going to get a seal backwards and I’m going to air check the clutch packs in the stack and in the transmission.

But if I can modify it and be accurate. I’m ahead a lot.
Changing a differential will ruin my highway rpm, gas mileage, and make the car a lot less friendly. Changing a transmission gear could give my .20 lower gear....giving me take off for my mild build 318 would be great. If I can add that with 0 problems while I’m already inside the transmission.....why would I not do it?

Do I think putting in that lower gear will work without modifying it.,..I think it will. I won’t run it until I’m 100% sure. I think this because places like A&A are seeking it without discussing modifications.

They are only seeking the sun shell and front planet with a thrust washer and snap ring
 
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This was some of the information I was looking at.
It says at the bottom of it you can just run a lower gear with no problems. ............................it’s an older post I found somewhere ........



I just went through 904 h*ll trying to match parts together. Let me share my story. . .

A long time ago, in a land far away. .. (ok it was only 6 years ago) I had a duster, that I wanted to put a 904 in. High 11 sec 340. nothing too special. From day one, the 904 gave me problems. The trans would flare the 2~3 shift, but only if I really wound it up (say over 6,000 rpm) To make a long story short, I replaced the following parts in no particular order. Valve body, pump/stator, high gear drum, input shaft/rear drum/ clutches/steels/bands/2nd gear servo/ int. band lever/ etc. . .basically every part in the trans. I finally gave up and put a 727 back in it. Well 6 years have passed, I have coleen steels, raybestos blue plate special race clutches, and an $800 turbo action converter, that I just can't give up on. So I decided to jump back in for my 416" EFI duster I'm doing right now.

At the time, I called every trans shop in the country. Nobody could figure out what it was. So this time, I really spent a lot of time trying to figure out what it was myself.

Well at the time when I put the trans together, in my infinate wisdom (I was only 20 by the way), I decided to put 5 rear (thin) clutches in my 4 clutch high gear drum. I'd seen this in pro trans' and other race type stuff, so I machined down my pressure plate, and made it all work. Now upon close inspection this time, I realized that the bottom clutch of the high gear clutch pack, was borderline to engagement on the rear clutch splines. What I figured out was happening, is that at low RPM, as the piston moved in the high gear clutch to clamp the clutchpack, even when the bottom clutch wasn't splined (indexed), it would simply rotate in to place and apply. But at high RPM the bottom clutch was spinning so fast, that it just kept skipping over the teeth on the rear clutch. Since it wouldn't spline itself, being the bottom clutch, it kept the entire clutch pack from clamping, thus causing the flare, until the point that the force of the piston caused the clutch to finally engage into high gear.

So because of all that, I have spent a lot of time looking and understanding the seemingly millions of 904 variations there are out there.

Here are a few things I've learned.


Any 4 clutch drum, will fit any 2 ring pump, as long as it is not a machined 5 clutch high gear drum pump, then there is potential for problem.

5 clutch drums will only fit machined
(clearanced) pumps.

If you plan on using a 5 clutch drum, you must have the correct rear clutch/input shaft to go with it. (this goes for 4 clutch stuff too, there are 3 clutch pack "colt" style stuff so pay attention!) If you don't use the matched rear drum/front drum the splines on the rear drum, will not completely engage the bottom clutch on the high gear drum.

Non lock up input shafts, CAN NOT simply be pressed into the mating rear clutch for a 5 clutch high gear drum. So if you're thinking of pressing out the input shaft of a non-lock up drum, to press into the lock up rear drum, you can't do it. The reason is, the snap ring location between the 2 are different. If you put the non-lock up input shaft, into the lock up style rear drum, it could move around .060. Which means the endplay could also move that much.)

From what I can tell there is only 1 input shaft/rear drum combo that will work to make a true non-lock up 5 clutch high gear drum combo work. It is a non-lock up 3 ring style, which uses a completely different pump all together.

There are several different high gear drums. Some even have different diameters which necessitates a different sun shell. There are 1 and 2 bushing types. There are also 2 different diameter stator supports. They only vary by about .050, so you have to really pay attention. The high gear clutch must match the pump/stator diameter.

Low gear sets can be switched out of late style 904's. but the thrust plate that go between the snap ring, and the sun shell must stay with sun gear. There are at least 2 distictly different thickness thrust plates in the sun shells.

You have to be very careful mis-matching parts together. The sealing ring heights on the different stack ups, can vary by as little as .100" from one style to the next. So what looks like it may work with no problem, if you have the end play set loose, it could cause some huge problems.


My advice to anyone that wants to run a 904 is to stick with an early style 4 clutch. The newer you get, the more variations and suttle changes there are. The low gear set can be simply swapped into your trans (78 and later 904/998/999trans have 2.74/1.58 gear sets) Just make sure you take the sun gear/thrust plates/spacer/planetary's and thrust washers as you will need all of those parts to do the swap. The 904 will hold a lot of power. Their light weight/small design vs. the 727 gives it a significant performance advantage on the right application. Just make sure you be careful when you start swapping parts because they aren't as forgiving as a 727 when it comes to part/year swaps.

Anyway. I hope all of my pain and time can be useful to someone out tHere
 
Some guy posts something on the internet so it must be correct. NO. You want to know why some things won't work, but the real question is if it ain't broke then why fix it. There are a jillion wrong ways to do things and automatics discussions are filled with them. You think you can put together a killer 904; first time out. I doubt that anyone here believes that. The information you seek is out there; you just have to sort it out from the 90% that is just cut and paste bs. I've been rebuilding these for forty years and I've never read a book or watched a video to figure out how. Forty years and I'm still extremely cautious when it comes to mixing parts. Yes, I built my 904 with a low gearset, but I didn't do any research; I just went thru a lot of parts in my stash until it all fit together. I have also rebuilt ones that came stock with the low gears that needed replacement..The new parts wouldn't fit. The supplier was real apologetic...great. You're not going to find anybody who has all the answers, but you'll find plenty of people who think they do. I know I don't and I know I never will.
 
I cannot recommend the books @VOETOM said to get enough, especially his. You will not regret getting all of those. That way, instead of possibly being steered wrong by people on a forum with terrible attitudes, you can read it for yourself in black and white from a known authority on the torqueflite transmissions. Tom himself wrote this article for Allpar.

Tom Hand's guide to the Chrysler torqueflite automatic transmission

We are very fortunate to have him onboard here and willing to help. I think you are doing fine. I'm glad to see you tearing into it. A lot of people wouldn't have the guts to do it. You can put a notch in your belt when you're done.
 
Oh I know exactly what you mean because even a congenial level-headed person like me can turn negative..like when this trans gets installed and doesn't work right...grrrrr. I care more about this trans working right than some medical professional somewhere cares about his patients living or dying. I assume that the op is an intelligent person and would be predisposed to enlighten himself with reading material if he saw fit. He didn't think so apparently..and neither do I. I can tell from his posts that he is capable of rebuilding this trans with the information he already has. Trouble is; he has too much. He's been advised to replace the tailshaft bushing. Nothing to it; right? There's a lot to it and he's probably going tomess it up. Bottom line it doesn't need replaced. He thinks a little flaking on the front band is ok. Would you advise him to replace it? I would and I did. What about spending over a hundred dollars for a rebuild kit? My opinion is NO. Wanna start slapping different gears in it? Oh great; more stuff to go wrong. And when things go wrong, people get frustrated. And when people get frustrated...they make stupid mistakes. What should he do with his belt if it has to come back out?
 
I am talking to him about getting his book. I also read the atsg manual twice.

The atsg Manual......it doesn’t cover worn out parts. Doesn’t much even talk about them.

It doesn’t go into flaking bands and when a bushing is worn. It just doesn’t say a whole lot. The information online...

THe threads....don’t even say a whole lot.
I’ve got more pictures of his transmission posted here than I could find in many other places. Beating the subject to death to get the slightest detail......

The output shaft doesn’t need to be replaced. None of the bushings do except the front pump. But why not replace them anyway just to get a feel for how they go in and what it takes to get them out. Just for the experience of doing so. I don’t necessarily like the look of the direct clutch bushing.

I know that I could put gaskets and seals in this transmission .....and it last many more years to come. The thrust washers show in spec and it took them a long time to get to the wear they are even at now. 126k and I will take way better care of it than the last guy that owned it that’s for sure.

We talked about earlier the steps and what needs to be replaced at minimum. That’s good....get a cheap kit and run it. I might do that.

It’s not that I think the flaking on the band is ok.....it’s...I don’t know how bad it is. I’m guessing it’s pretty bad now.

It would be great to have a 2.74 gear in there. I would like that. It would go nice with the cam I want to run.....

It’s just a matter of getting the right ones in there. Then the tf2 kit.

What I don’t like is replacing so many things at once.
But that’s how it needs to happen.

I’ve done engines like this and had to learn how to tune them because of changing too many parts. It’s a concern. Changing the carb, timing chain, distributor cussed me a lot of headaches.....but it also helped me understand many things about each of those things.....especially the carburetor. It was a nightmare learning to re set up a used Holley.

If it has to come back out. I’ll pull it back out and back apart the next weekend and try to sort through what went wrong and why.
Honestly
........what do you see going wrong.

I just need to know if I can get 2.74 gears in there and how.....
The rest of it.....I’m getting the hang of it. I’m getting an understanding of it and I’ll pay it forward.

When it goes back in.....it will be right.
 
The excerpts I've seen ramble on and on about transmission theory. Who cares? If somebody needs a book to tell them how to disassemble something and the assembly is the reverse..they're not the type to catch imperfections that will ruin their build. ...You posted on here because you know that every transmission is different and if you post enough pics maybe somebody will see something not obvious to the untrained eye. For instance, that front band will work for a while, but the flaking means it's begun its way out. Might last 15-20k. Installing bushings is an art. (Removing them is too) If you're a bushings artist then jump right in...but if you think you can replace all those bushings and not mess any of them up..think again. You'll be buying several of each. And after they're installed, they might be out of round and cause binding. Then they'll spin under load...It's not a carburetor..You don't have to jack up the car and remove a heavy object from underneath something to redo a carb. Engines are simple. You have eight of all the same thing. You still have a long way to go; clutch pack clearances (just wait til you hear all the differing opinions on THAT one), end play; and how to adjust it, assembling the pump (? ohya). So now maybe stack up all your steels together and you'll be able to tell if any are warped. Sometimes they get dished from more heat nearer the center. Lay them on a top pressure plate and see if they teeter totter. I haven't really seen a good pic of the rear band yet. Oh and if this thing has to come back out the next weekend..that's a FAIL.
 
CudaFactHackJob said:
The excerpts I've seen ramble on and on about transmission theory. Who cares? If somebody needs a book to tell them how to disassemble something and the assembly is the reverse..they're not the type to catch imperfections that will ruin their build. ...You posted on here because you know that every transmission is different and if you post enough pics maybe somebody will see something not obvious to the untrained eye. For instance, that front band will work for a while, but the flaking means it's begun its way out. Might last 15-20k. Installing bushings is an art. (Removing them is too) If you're a bushings artist then jump right in...but if you think you can replace all those bushings and not mess any of them up..think again. You'll be buying several of each. And after they're installed, they might be out of round and cause binding. Then they'll spin under load...It's not a carburetor..You don't have to jack up the car and remove a heavy object from underneath something to redo a carb. Engines are simple. You have eight of all the same thing. You still have a long way to go; clutch pack clearances (just wait til you hear all the differing opinions on THAT one), end play; and how to adjust it, assembling the pump (? ohya). So now maybe stack up all your steels together and you'll be able to tell if any are warped. Sometimes they get dished from more heat nearer the center. Lay them on a top pressure plate and see if they teeter totter. I haven't really seen a good pic of the rear band yet. Oh and if this thing has to come back out the next weekend..that's a FAIL.
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Man, lighten up already. You're not the only one in the world who can build a torqueflite and get it right. It's ok. It's not your transmission. You cannot learn something for someone else, they have to learn their own way. Let him do it. He'll learn more in the long run. We're all trying to help, but in the end, everybody does things their own way.
 
The low gear sets are easy to find. ANY V6 auto Dakota, Durango, Ram 1500, or 1500 Van, or XJ Cherokee or other Jeep that used the 42RH or 42RE (A500). Also Diplomats, 5th Avenues, etc... Basically anything that used a 904 based transmission after 1980 or so. If the pan shape is the same as yours it's A904 based.

The ATSG manual makes a couple assumptions. First, they assume you know how to disassemble and reassemble a transmission. Second, they somewhat assume you will be replacing standard wearing items and anything else that appears worn or damaged. There is also an assumption that you have the tools and ability to accurately measure clearances.

In my experience the internal bushings probably don't need replacing, but thrust washers generally do. If I buy a kit before I disassemble, I but the master kit with the bushings. If I don't need to change the bushings, I don't. New clutch friction and steel plates and thrust washers will usually get things reasonably close (as close to spec as it may have been when it left the factory perhaps).

I mentioned Transtar because they have retail locations in most cities. Why buy on line if you can support a local business? Also, if you need any other components like selective spacers or maybe a used low gear set, they just might have one on hand. Pretty good chance the fellow behind the counter is a car guy who knows from transmissions.
 
I don't like new thrust washers because they have unfinished surfaces and they shed metal until they are broke in; at which point your end play opens up. I know if I use used thrust washers then my end play will stay where I set it. So true that the manuals are for experienced transmission mechanics. But, this thread is not about learning. It is about having a working reliable transmission that doesn't leak. If the op's learning method or perspective is not applicable to automatic transmission repair then it has to be adjusted in order for the job to be a success. We have a long way to go, much further than the op's original assumption; and if he has the patience with himself then and only then will he be successful. So after the steels are checked, he can order the appropriate parts. I still haven't seen the rear band clearly, but they're usually okay, so I would check out my local parts places like AZ Pep Boys, etc, not NAPA; for kit prices and a pump bushing and see if they can get the thicker little thrust button that goes on the front of the output shaft. Front bands on ebay are $10.23 free shipping. Not a good place for kit prices. Edit; there's one for $5.05 free shipping
372650762905
 
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CudaFactHackJob said:
Please do NOT stand the trans on its output shaft for any reason.. That is incorrect information.
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What makes you think that is incorrect information?
Makes perfect sense to me as a way to ensure an accurate measurement.
Exactly what do you think happens to the output shaft at 60 mph when you hit a bump and the suspension travel forces the driveshaft to slide inward.?
 
glhx said:
View attachment 1715357539
His is the front planet set. Both of these thrust washers run .048
Are these not supposed to be .061 as said above?-

View attachment 1715357540
These are the rear planet set thrust washers. They run similar to the front......
.048 and .049 front and back-

View attachment 1715357541 -
This is the thickest washer. The one with the tab on it. It measures .124 .........The replacement shows .121 online.
I’m guessing*this one is fine.
However....look at the inside of it. Is that supposed to be that way or is that wear. I can’t get the caliper in there to measure it. This still has most of its copper color intact on the other side.
EDIT: (this washer controls the planetary gear train end play. The cut out in the middle that is mentioned above....that’s cause by the snap ring wearing into the thick washer. I think the spec for planetary gear-train endplay is .005-.045. If it shows out of spec. You can replace this washer AND THE SNAP RING)
The planets thrust washers should also be considered here. Mine is not out of spec. If I had to try to get it back into spec. I would measure the outside surface of this thick washer. Then replace it. And then check the spec again....then replace the planets thrust washers.....
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I have never seen that washer in good shape. The snap ring digs into it and causes increased endplay over time. I would replace it and the bushing in that assembly is always worn as well imho.
 
glhx said:
Can I get a newer sun shell with the 2.74 gear and planet and just set it in there with no other modifications

I would rather lower the gear in the transmission than the differential. I guess I could just get it and see how it goes. I know they sometimes match to the 5 disc clutch and a different pump.
But I also see the hp trans shops selling them as standalone upgrades. My car runs a 2.73 gear set and I would like to keep that. If you guys know for sure. I would like to know. I’ve researched the hell out of it and find all sorts of information where people have run this....but nothing definitive. Nothing that says....yes it works and this is how.

Basically like the ones in the picture
View attachment 1715358156
If I put all that in my 904......will it work with no other modifications. -
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Yes
 
CudaFactHackJob said:
What makes you think that's a low gear set?? Maybe you should concentrate on fixing your transmission to stock without screwing it up. The usual experts aren't chiming in because they're just lurking back and shaking their heads after reading some of the strangest advice they've ever seen; spending $105 on a rebuild kit, replacing the tailshaft bushing, standing the trans on the output shaft, . I see a lot of first timers trying to do a bang up job; just to end up with $500 worth of incompatible junk. You spend hours measuring perfectly good thrust washers yet you want to use a flaked band.
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You can always tell a low gear set by the unique shape of the sunshell. It has a raised section on the back versus a flat section on a standard 2:45. The picture he posted is a 2:74 gear set or low gear set.
 
CudaFactHackJob said:
What makes you think that's a low gear set?? Maybe you should concentrate on fixing your transmission to stock without screwing it up. The usual experts aren't chiming in because they're just lurking back and shaking their heads after reading some of the strangest advice they've ever seen; spending $105 on a rebuild kit, replacing the tailshaft bushing, standing the trans on the output shaft, . I see a lot of first timers trying to do a bang up job; just to end up with $500 worth of incompatible junk. You spend hours measuring perfectly good thrust washers yet you want to use a flaked band.
Click to expand...
If you look in my profile you will see many pics of my rollerized drag race 904. All done myself. I am hardly a first timer. Rebuild the 47re in my diesel Cummings as well. Works fine.
Measuring thrust washers with a caliper or micrometer is absolutely the correct way to inspec them. That is why the thickness are listed in a repair manual. I agree the band is so so condition.
 
glhx said:
Years ago.....when I was in my early teens. I got ahold of a non running car that no one wanted.

I knew nothing about it. I had no one to teach me anything about it. When I blew up the engine by running it low on oil. The people who knew what was happening just laughed as they watched. After the fact. They told me what I did. I’ve built several engines since. Not one of them has blown up. I still remember them laughing and the correction after the fact.

The deal is. I don’t know how to do this. It’s my first time. If I blow this transmission to the moon. If it ends up in outer space....or in the trash can. That just is what it is.
I’ll figure out my stupidity or my lessons. Then go get another one and do it again.

So......yes I spent an hour checking clearances.
Because I want the experience. Now I know off the top of my head what each one should run and what they are all called. What they all do and how each washer fits into the equation. This whole inner workings of this this are a complicated process. There are things I don’t know. I know the governor controls shift points. I don’t know how yet. They say a ten year old girl could do this. I want to meet one. Is it simple.....yeah. But is it simple to modify it. Not really.

Is the reverse band flaking.....a little bit. I’ve already decided to replace it......I did scratch it to see how brittle it was. It wasn’t bad. Both drums have no hot spots on them and lots of friction left....the question is.....what shape is that friction material in?

Standing the trans on the output shaft. It reads .040
Not standing it on there....it reads .050

The Manual doesn’t say to stand it up on the output shaft. So I didn’t take that reading into account. However....to satisfy both people without getting mad at me. I did both. Both readings are within the factory spec so I knew it was ok.

Your one of the only ones even giving advice.....it’s valued. Even if it’s beating me up a little. I don’t care. It’s welcomed. Learning is a messy process when your dealing with older worn out stuff and you don’t have a good base on what it was like new and have never seen one before.

I have seen some of the experts say to stand it on its end. Since I don’t know....and I don’t know why.....they do this and others don’t. What do I have....realistically? Think about it. I really don’t know.
I think that way because I’m in the medical field and in that environment. You cannot be wrong. You have to know.....and you have to be sure. Which is why I know by the time this goes back together it will work well.....all these measurements to me are like a set of 50 medical lab value measurements telling me what’s wrong with someone and why. Then how to fix them

If I toss the idea around about using parts that are older. It’s because I don’t know how much life is left in them. Hell....I can’t exactly measure a reverse band. I see that it’s super thick....intact and has 99% of its surface area. I see a perfect drum with no hot spots. So how can I possibly know if it’s good or bad. It’s been in there 45 years and still looks almost like it was just put in there.
So how could I know. It might be a total waste of money buying a new one. Since I budget this and I’ve blown this years already....I can’t exactly go back. The experts would know whether to replace it or run it.....I don’t and I do t exactly have a way to know except look on here where several are saying that the reverse band never wears out. So they don’t replace it.

I probably annoy the experts. However.....I’m very good at what I do because I ask the questions that are advanced and basic so I have complete understanding.

I have to replace the parts based on ignorance. Based on lack of experience. I don’t think too much....I’m not over complicating this. I’m getting information to make sure the patient survives..... it it’s just a transmission and can be replaced. It’s not a human so there is room for mistakes......but I still think this way. I can’t turn it off just because I’m not at the hospital.

If the experts want to watch me blow this thing up. I’m fine with that. Of course I don’t want that. I’ve looked at every post I can find about them talking and even arguing about this stuff. I have to sort through all the info of them talking about it.

Many times they talk to people like those people know and have the same expertise they do. When my friend wi5out kids asked why my 7 year daughter was asking so many questions about how to play the simple game of battleship. I simply told him that she’s 7 and knows nothing. She’s not in her thirties. She really just doesn’t know and he forgot that someone could not know something so simple. I’m like that with transmissions. Hell....I’m not even a novice.


So....after my stupid rant.

What makes me think that’s a low gearset is the stepped sun shell. There is only one that looks like that. Of course I would confirm that before buying it. I would even ask him to measure it some. He has the front planet turned the wrong way so I can’t see it. That particular planet from that side looks like the one in the older style . The other sun shell with the front and rear sun are the same. That’s the one I have.
What I don’t know is about that stepped sun shell yet. I don’t know the spec and as I have seen several people sell them as bolt in high performance parts....I’ve seen where lots of people run them. They don’t talk about them as far as matching parts. They talk of 5 drum clutches and beveled pumps....they talk about machining pistons and adding clutches to 4 drum....they talk about the 999. They don’t go into do these things work individually. There is a lack of detail in the information. They do all kinds of mods at once. For me....I think 4 clutches are fine. You also have to remember. It didn’t make sense that I even had 4 clutches a few weeks ago. Now I know they do and why. Bigger cars needed them and Chrysler could not afford to redesign the transmission. Which is also why they put lower gears in there. To keep the highway rpm down but give the bigger 70s cars good take off. They could not afford to make an overdrive transmission so they went cheap and did this.

I now know an overdrive 518 won’t fit without going through hell. I also know now that I can’t convert this to a lock up clutch.

If I put this transmission together right now. With all the same parts. It’s going to run fine. It came out running with no apparent defects. Which means if I just add a few parts to tighten it up and keep close track of the adjustments it should work just fine. There are always variables The would show otherwise so I can’t say that 100%that it will work. I’m not going to get a seal backwards and I’m going to air check the clutch packs in the stack and in the transmission.

But if I can modify it and be accurate. I’m ahead a lot.
Changing a differential will ruin my highway rpm, gas mileage, and make the car a lot less friendly. Changing a transmission gear could give my .20 lower gear....giving me take off for my mild build 318 would be great. If I can add that with 0 problems while I’m already inside the transmission.....why would I not do it?

Do I think putting in that lower gear will work without modifying it.,..I think it will. I won’t run it until I’m 100% sure. I think this because places like A&A are seeking it without discussing modifications.

They are only seeking the sun shell and front planet with a thrust washer and snap ring
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If you learned to rebuild an engine that worked, you can rebuild the Torqueflite. Everyone can learn if you are mechanically inclined.
 
C130 Chief said:
The low gear sets are easy to find. ANY V6 auto Dakota, Durango, Ram 1500, or 1500 Van, or XJ Cherokee or other Jeep that used the 42RH or 42RE (A500). Also Diplomats, 5th Avenues, etc... Basically anything that used a 904 based transmission after 1980 or so. If the pan shape is the same as yours it's A904 based.

The ATSG manual makes a couple assumptions. First, they assume you know how to disassemble and reassemble a transmission. Second, they somewhat assume you will be replacing standard wearing items and anything else that appears worn or damaged. There is also an assumption that you have the tools and ability to accurately measure clearances.

In my experience the internal bushings probably don't need replacing, but thrust washers generally do. If I buy a kit before I disassemble, I but the master kit with the bushings. If I don't need to change the bushings, I don't. New clutch friction and steel plates and thrust washers will usually get things reasonably close (as close to spec as it may have been when it left the factory perhaps).

I mentioned Transtar because they have retail locations in most cities. Why buy on line if you can support a local business? Also, if you need any other components like selective spacers or maybe a used low gear set, they just might have one on hand. Pretty good chance the fellow behind the counter is a car guy who knows from transmissions.
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Those lockup trans are the best ones for a performance build as well because most of them came with the low gear, five clutch front drum, 4 pinion steel planetaries, all the beefy 999 parts.
The lockup is fairly easy to get rid of.
 
The driveshaft better never push the output shaft forward. The sun gear can be switched in the low gear shell.
 
CudaFactHackJob said:
The driveshaft better never push the output shaft forward. The sun gear can be switched in the low gear shell.
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The op already posted that there is a .010 difference in his measurement by standing it on end. To me that makes Rick Allison recommendation valid. Your driveshaft can absolutely punch that small .010 slop around the snap ring in the tail shaft forward.
What you don't want is to have the output shaft pushing the drums into the pump. That's why there is a spec on the input shaft.
I understand that it can be switched but I have never done it.
My point was that the op correctly identified a low gear set and you questioned him on it as if to say he was not correct.
 
I wouldn't assume there is a low gearset in that group just because it has that shell with it. It very well could be switched; plus the fact that it was identified as a 904 gearset. Go ahead and think the driveshaft pushes the output shaft forward and that it's a good idea to set the trans up on the output shaft (I don't care who says to) but you are only repeating incorrect information.
 
CudaFactHackJob said:
I wouldn't assume there is a low gearset in that group just because it has that shell with it. It very well could be switched; plus the fact that it was identified as a 904 gearset. Go ahead and think the driveshaft pushes the output shaft forward and that it's a good idea to set the trans up on the output shaft (I don't care who says to) but you are only repeating incorrect information.
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I am in the middle of a refresh on my 904 right now. On my bench last night, I verified what the op has posted. If you push very firmly on the output shaft, your input shaft reading will very.
I believe the reason Rick Allison recommends to stand it on end is to use the trans own weight to get the output shaft all the way forward. I would call it a trick to ensure an accurate reading from a very experienced Torqueflite expert.
We are not talking a huge amount here, but it does move slightly.
I have no problem when people disagree with might posts, but please be courteous and explain why you don,t agree.
I agree the 904 parts could have been substituted, but usually when someone is selling a low gear set, you would sell all the parts as an assembly because most of them are required.
 
I didn't say it wouldn't move if you pushed in on it. I can't comprehend how you can't understand that the driveshaft can never push the output shaft forward or it will destroy the transmission. The yoke must never bottom out on the output shaft; that's why there's plenty of room for it to slip in and out. You're a more trusting soul than me if you believe that that's a low gear set, the seller says it's 904 and purposely (I think) has left out pics of the front of the sun gear. In the seller's defense tho, I don't remember the ad stating that it was a low gear set. I could be wrong about that; I just don't want to bother looking at the ad again. I will wait for the op to post his progress before I post again. Maybe someone else can chime in on those two issues for you.
 
CudaFactHackJob said:
I didn't say it wouldn't move if you pushed in on it. I can't comprehend how you can't understand that the driveshaft can never push the output shaft forward or it will destroy the transmission. The yoke must never bottom out on the output shaft; that's why there's plenty of room for it to slip in and out. You're a more trusting soul than me if you believe that that's a low gear set, the seller says it's 904 and purposely (I think) has left out pics of the front of the sun gear. In the seller's defense tho, I don't remember the ad stating that it was a low gear set. I could be wrong about that; I just don't want to bother looking at the ad again. I will wait for the op to post his progress before I post again. Maybe someone else can chime in on those two issues for you.
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In an earlier post you said it does not move. The op and I have both verified that it can move a very slight amount that is enough to effect your input shaft reading. That is the point of this discussion.
I am sure you understand that as your rear suspension travels up and down that the driveshaft yoke slides in and out of the tail shaft.
I never said anything about the yoke bottoming out on the output shaft. I am just saying that when driving the car at speed and encountering to rough terrain the the extremely rapid sliding of the yoke would be enough to cause that slight movement in the output shaft to move forward. You want the tail shaft bearing snap ring to be the movement limiter and you want that limit to be reached before the output shaft drives the drums into the pump. That is probably the engineering reason for checking the input shaft end play or at least part of it.
You will note that when I posted the pic of the page where Allison says to stand it on end, he also has a different endplay tolerance recommendation. I have seen several areas of the Torqueflite where experienced builders have an alternate method that they consider to be more accurate. I have seen alternate recommendations on how to adjust bands that are not based on number of turns, but on the length of servo travel for example.
I have already agreed on the low gear set. Obviously I would verify what I was buying. I am going by the op picture which judging by the sunshell is a low gear set.
 
Please post a quote of my post saying that the output shaft does not move so I can edit it. But you are incorrect in saying that the tailshaft bearing snap ring limits forward travel of the output shaft. The bearing limits rearward movement of the tailshaft; whereas the snap ring does almost nothing. Sort of like the snap ring on the front of a th350 output shat; it has no purpose. You're overthinking any effect the forward movement of the yoke can have on forward movement of the tailshaft. As if the yoke can push the tailshaft and all internals into the pump; destroying it..no way. I would not advise the op to purchase the gearset unless I was prepared to reimburse him if it isn't want he wants. I would feel responsible in giving such advice if it was incorrect.
 
CudaFactHackJob said:
Please post a quote of my post saying that the output shaft does not move so I can edit it. But you are incorrect in saying that the tailshaft bearing snap ring limits forward travel of the output shaft. The bearing limits rearward movement of the tailshaft; whereas the snap ring does almost nothing. Sort of like the snap ring on the front of a th350 output shat; it has no purpose. You're overthinking any effect the forward movement of the yoke can have on forward movement of the tailshaft. As if the yoke can push the tailshaft and all internals into the pump; destroying it..no way. I would not advise the op to purchase the gearset unless I was prepared to reimburse him if it isn't want he wants. I would feel responsible in giving such advice if it was incorrect.
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There are 2 snap rings. One keeps your bearing in position on the output shaft. When you put your output shaft into the tail shaft, you spread the other snap ring through the removable cover. That snap ring locks the outside diameter of bearing into position.
Even though it's locked, there is still a small amount of movement that is possible. Snap rings can take a tremendous amount of force.
A small snap ring holds your entire planetary assembly from coming apart. If you can push your output shaft forward with your hand on your workbench, you don't think the inertia of the driveshaft sliding on the yoke at 60 mph can do the same. There's all kinds of forces there.
I have answered the low gear set multiple times. The op posted a picture of a low gear set. A picture. I did not tell him to buy anything. I said he was correct that the picture he posted with the unique sunshell is what a low gear set looks like and that if he used all those parts, he could put a low gear set into his trans assuming the parts look like the ones in the picture.
Perhaps you need to provide an explanation as to why you check the input shaft endplay. What do you think is the reason those specs are provided.?
 
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