Inspection of a 904 torqueflite

[glhx]

I just tore down this 904

I’d like to know what kit to buy or what separate parts are needed to refresh this or whatever it needs.

It had no problems shifting before I tore it down. I had recently changed the fluid. There was a lot of black powder in the pan when I pulled it to do the change....
So this time there was very little. It was probably run 50 miles since the change. I tore it down because the torque converter hub was cracked and tore up the bushing it rides on.
I figured if that was bad....what else was bad.

This is the first time I’ve ever taken apart and transmission. I have a general idea of how it works. Some of the forward clutches looks like they were pretty rough compared to what they should look like.

It looks like I was about to lose all my forward gears

I’ve got about 50 pictures I’m going to post of the wear on these parts.


Reverse band.....I don’t even know what this is supposed to look like. Are there any upgrades for this. It doesn’t look as worn as the other band -


Don’t know what this is. It has a thin bushing in it. Should I replace the bushing. It also looks like something sits or turns where it’s shiny -


The reverse clutch packs didn’t have the gouges taken out of them like the forward clutch pack did. This one just has this one spot where it’s gray. That’s gouged in a small place but I’m sure it gets worse after they get beat up like that -


Looks ok. Doesn’t mean it’s good. This is one of the reverse steels. How can you tell if these are good and can be kept. Or bad and need to be replaced?-


A typical example of the reverse clutch. This one is intact -


a picture of the output shaft,......-


One of the reverse steels......the one has the wear marks on it. Those round line Pattern like it needs to be polished -


Another reverse clutch pack. Looks a little worn....you can see where it has penetrated the surface and gotten a little rough in places -


Looks like the reverse Simpson gear set. What are all the gouge marks from. All the rough texture inside there. The gears felt fine. They seem tight and don’t have a loose feel by hand to them. -


A picture of the upper end of the output shaft. Those two polished parts ride on the copper color bushings that are pressed in to the clutch packs or other parts like them-

I left out pictures of the other steels and reverse clutch packs. They look the same as the ones above. No burn marks on them. Very little gouging or friction surface broken down.
The forward gears are nothing like this. Much worse.

All that black stuff I found in the pan before this trans fluid change was friction material.
I changed it because it was leaking badly. The seal on the area where the valve body comes out of the transmission to shift it......went bad. I had to pull the valve body to replace it. As I didn’t drive it much.....it didn’t have time to keep trashing the friction material. It would have with more miles and I would have had more in there until losing all forward gears. I just had a turbo 350 lose all forward gears like this. I’m guessing this is exactly what happened to it

 

[glhx]

Here is a better picture of the journals on that output shaft -


Good picture of a Simpson gear set. Looks like a small notch in one of the teeth -


One of the forward steels.....looks ok-


Journal of the Simpson set. You can see the the notch in the teeth better. I’m guessing this was caused by something and not like that from the factory-


Bearing race of the reverse drum.......-


This is the surface where the reverse band grabs the reverse drum-


some sort of thrust washer sits here -


This is the view of the bottom steel in the reverse clutch pack.-


Spoke too soon. Here is a reverse clutch pack friction. This one is gouged pretty badly. -


And the top steel. It’s a lot thicker than the others. Looks fine to me......but I don’t know. This is my first transmission taken apart.....ever-

 

[glhx]

Now we can look at the forward clutch packs. They are trashed.
I would like an estimate on how long this would have lasted like this.
Since all the seals were leaking. This transmission was run low I’m guessing. How low? I don’t know. Or.....maybe it’s just old and worn out and wasn’t run low.


This one is worn down. Worn is what it should looks like, but this one is gouged out in the lower part of the picture -


This one has a waffle type texture to it. It’s rough in areas where it ate all that up-


Trashed forward friction plate. -


Forward steel. That’s a burn mark on the left. Not one on the right...that’s just glare-


This one sat in the bottom of the stack. I don’t know if it supposed to have that ring or not.-


A clear example of a burn mark on this forward steel-


Here we go......this was the worst friction plate. It’s totally trashed. How long do they last when they get like this.-


This one has no burns in it. Just a wear pattern-


Bottom view of the forward clutch drum. The stack sits down in there. See the matching wear pattern. What causes that?-


Burn mark up in the corner-


These are the copper colored races. This shows the wear pattern and the inner part of the forward drum. I don’t know if any of this needs to be replaced or not. -


Outer part of the forward drum. The band grips this to stop the forward drum and change the gear ratio.....I think -


This is the extent of the war on the forward band. The rest of it is solid-


Another picture of the forward drum where the Clutch packs sit down into.....again...lithe ring pattern-

The rest of the pictures show the bushings and servos of the transmission

 

[glhx]

Haven’t taken out the front servo yet. I’m sure there is some black funk in there as this seems to be a place where the fluid doesn’t cycle as much. The back servo had very little of this though, so maybe this one won’t-


The output shaft rides in this piece. There is a wear pattern on the aluminum. Is it worn out? I don’t know -


This is a tail shaft bushing. It looks steel. It has some wear patterns and looks eaten up in some places -


What the fluid looks like with friction material in it. This was in the bottom of the pan-


Another of the tail shaft bushing-


accumulator housing.....do these wear?


This bolts to the back of the main transmission housing. It has wear patterns. There is a picture of it above as well. It’s all aluminum. Do these typically get replaced?-


Main housing. That’s where the overrunning clutch goes. There are large needle bearings and springs. I’ve seen where people replace the springs and bearings but leave this part in there?-


Valve body......black coating is friction material fluid that leaked out when I turned it upside down-


Rear servo arm pin....housing. The pin that holds the servo goes here, there is a wear pattern -


The pin had black film on it-


Rear servo piston-


This is the forward clutch drum before I took it apart. There is wear on the bushing.....but I don’t know if we replace these when they are like this or not. The clearance is shown between the clutch packs and the snap ring. I’ve heard this is measured with a feeler gauge. I need to know about this-


This pin is for the rear servo arm. That o ring leaks and goes out the tail shaft seam. It’s rare the or ring leaks but I’ve heard when it does it’s hard to track down and the tail shaft has to come put.
You screw a bolt into the back of this pin to get it out. It slides right out and the tail shaft is what hold it in there-



That’s all I have for this. I have not taken apart the front pump yet so I don’t know what that looks like. I know the bushing that the converter rides on it eaten up but that was brim a cracked torque converter hub which is common with these 904 transmissions.

I could have just pulled the pump and put a new bushing in there and maybe gotten some Mike out of it. I figured the transmission was not far behind and I didn’t know what had ever been done to it.
I can say that it was painted ford blue so it has been out of the car.
I can’t say if it was even original to the car. It was out of a 318 76 charger.

I won’t be driving this car much. I don’t really drive the car hard at all and don’t need performance parts. Maybe a shift kit.

 

[missing linc]

Unfortunately, I don't know much about transmissions, the short time I worked in a trans shop, I was only a grunt, limited to doing the R&R work and a few clutch jobs, I wanted to learn to build them, but boss said he had no need of another builder at that time. I did get to know one of the builders well, and when he opened his own shop I hung around there frequently, hoping for a job, but he was never busy enough to need another employee. I did learn a few things from watching him, and one that I remember is that the steels are extremely durable, as long as there are no hot spots or blue areas, a light sanding to rough them up is generally all that is necessary. Excess heat is the main cause of transmission failure, and if you had a leaking seal for and extended period, fluid was probably low on a regular basis, which leads to heat build up and wear on parts. Absolute must when reassembling the trans is CLEAN! Everything must be clean enough to eat off of. Any contaminants in the case will cause premature wear and failure.

 

[Garrett Ellison]

Written by a member of the site, highly recommended by many other members for anyone who is going to tackle an automatic rebuild. Chrysler TorqueFlite A-904 & A-727
That being said, some of that wear and tear looks pretty significant and some looks like witness marks that someone else may have been inside of it before you.

 

[Murray]

Just looks like normal wear on an old trans. Beware of the rear spragg, should upgrade here, other than that a good rebuild with quality parts.

 

[glhx]

Just looks like normal wear on an old trans. Beware of the rear spragg, should upgrade here, other than that a good rebuild with quality parts.

What can you do to upgrade the sprag?

 

[Murray]

Spraggs seem to fail unexpectedly for reasons unknown to me. The replacement bolt-in spragg is very reliable. Real tranny pros may have recommendations as to specific clutch/band material. Always replace the convertor. You can do it.

 

[Garrett Ellison]

The rear tail shaft bushing looks like someone gouged it with a chisel. A&A and ATI both make bolt in sprag kits, and Transmissionbench.com carries a lot of hard parts from Sonnax.

 

[CudaFactHackJob]

I disagree with everything that's been posted.

 

[CudaFactHackJob]

Let's start out by clarifying basic terminology. The first drum in the front is not called the forward drum. It's the front drum, direct drum, or reverse/high drum. The next drum out; the one that has the input shaft stuck into it; is called the forward drum because it is used for all forward gears.

 

[CudaFactHackJob]

Replace all your frictions and steels and be done with that part. Your tailshaft bushing and sprag are fine. The planetaries look chewed up so i would also check the sun gear and the ring gears. If you can hang your fingernail on a scored part then it's bad. Don't forget to check the inside front of the front drum where the rings ride for scoring.

 

[70aarcuda]

Spraggs seem to fail unexpectedly for reasons unknown to me. The replacement bolt-in spragg is very reliable. Real tranny pros may have recommendations as to specific clutch/band material. Always replace the convertor. You can do it.

The bolt in sprag is the same as the sprag that is in the trans already...10 roller with springs......
If the cam and retainer are damage...you just drill the pins out and replace it with a cam and retainer that has screws...no different...takes the same 10 rollers and springs..

Just buy a new spring and roller kit.....for 5 bucks off ebay....

The sprag did not change until the 1988 models.....then the one piece caged sprag was used...otherwise they are all the same...

 

[glhx]

I see what you mean by calling the parts the wrong names.

What about all the other parts?

How do the other bushings look?

So far I’m going to replace
Gaskets
Seals
Sprag bearings and springs since they don’t cost much
Friction plates
Steels
The front pump bushing.



As far as the other bushings go....I don’t know. Depends on what it takes to get them out and back in. I’ve seen where they use special presses that I don’t have. I’m wondering if there is something else that would do it.....like a cam bearing installer. I do have a good one of those laying around.

I don’t know about the output shaft holder.....it looks like the output shaft rides on it.

And I’m looking into replacing the planets if they are bad.
The sun gear looks ok. I’ll post a picture of it

Should I put any sand paper to the the surfaces that the bands ride on? Like some 400 emry cloth

 

[CudaFactHackJob]

The cheapo kits are okay really. The deluxe kits don't have anything great in them. How many frictions did each drum have? and what about those planetaries? They looked ragged. Is the inside of the direct drum scored or not? Ya 400 is good around the drums.

 

[glhx]

The ring gears inside Where the planets ride look good. They aren’t chewed up like the sun and planets. Both of the sun gears are not as chewed up. The tops are ground some and have that wave to them.

The planet gears have very little play in them

The front ring gear. Has those teeth that the clutch packs sit into.
Those teeth have wear on them.....on the lower area

I’ll post some pictures of them both.

Where the steels go up and down......there is no scoring at all.

How many friction plates are in each drum. There are 4 of them on the forward drum and direct drum.
I thought there was supposed to be one with three and one with 4.
But....they both have 4

 

[glhx]

-
The forward drums clutch pack engage into this. You can see where the teen are not straight. Also.....look at this thrust bearing....I think that’s what it is. It has copper coating on it


another picture of the teeth. -


This one is a bit more clear-


Both of the sun gears look like this one. Not too bad but has wear. Or maybe it is bad. I don’t know what is considered bad. They still mesh fine. I don’t put a lot of power down so maybe that’s why it didn’t blow up. I’m not sure. -


Almost all the copper is gone from this thrust washer. What does this mean? Do they need to be replaced? Does this mean that the surface they sit on top of is worn down?-

So what does all this mean? The planets are chewed up. Does this mean they will strip out or cause play?

What caused them to be eaten up like that. Maybe torque converter parts from the cracked hub? Why didn’t it trash everything else?

 

[glhx]

Does this need to be replaced? -

 

[70aarcuda]

those thrust washer are .060 thick...measure them......if there is alot of play....in the trans..the thrust washer going to take a beating.....

a thrust washer kit is about 30 dollars....replace them all

 

[70aarcuda]

I would be searching craigslist for a rebuildable 904 core to use the hard parts....it would be cheaper then buying the individual hard parts

 

[glhx]

-

Will this one fit....kits about $70 or so

Edit: it won’t fit. I’m pretty sure the sun gears is smaller and has the little raised spot on the back where it meets the sun.

My shell doesn’t have this.

However. When you replace them as a set like this. It might not matter

 

[glhx]

Which one of these pictures makes you think I should start with a different core?

Is it the thrust washers or the hard parts?

Also.....let’s say I do get a difference case.....
What would it take for me to get overdrive? I would rather have that. Or convert this one to overdrive.

 

[VOETOM]

GLHX, this book has an awful lot of pictures, a large amount of technical details, and answers most everything you have asked so far. It is pretty good source for folks that have not rebuilt too many Torqueflites before.
Tom

 

[VOETOM]

And these two are also good to have, especially a factory shop manual. There are all the technical details you'd ever need to know listed in them. The TF changed through the years but the way it worked stayed pretty much the same.
Tom