904 Transmission Stopped Going Into Gear

-
Yep, I'm definitely not giving a shop that kind of money when I can take a stab at the rebuild in my garage (with some FABO help of course). Thats half the fun of this anyways, learning how to do stuff.

On that note, I started disconnecting my 904 in prep for removal.

When I started loosening the front cooler line it felt really tight. When I finally got it off this is what I found:

20180521_075704[1].jpg


The line had been completely twisted shut when the previous owner tried to install/tighten it. It was hanging on by a sliver that broke when I loosened it.

So the trans was getting very little or no flow to the radiator. That might explain it chewing up bands.

Anyone know who makes a good 904 cooler hardline set?
 
AJ/FormS said:
Wow! that's a lottacoin for a couple of hours work.

I have convertors from the 70's that I'm still using, although none were involved in serious meltdowns. Transmission shops used to flush them for a small fee.
Click to expand...
Yup, and those old converter flushers were about as effective as now going to a lube shop to get your transmission flushed. Yes, it will get rid of the old oil, but cold solvent could never get the crud out of the vane areas. The most effective cleaner is hot ATF.
 
Yep and those Aamco guys would flush and fill yours tranny plus adjust the bands for the cost of the fluid .
 
transman said:
And you could get a beer for 25 cents.:lol:, and my brand new 71 340 Duster cost around $3100.00 or so on the road.
Click to expand...
I bought my slightly used 1970Swinger 340 4-gear in late summer of 1970, at the tender age of 17....... with half the money coming from my piggy bank of paper-route earnings. It had 11,000 miles,the tires were new appearing, she was Panther Pink, and I talked the newly become Dad, down to $2400Can.
The following summer I turned 18 and beer was 35 cents for a pair of draft. IIRC gas was 37cents a gallon. And on Sundays, at time and a half, I was pumping gas for around 1.50 an hour.

Oh yeah, the bank loaned me the other 1200, but IIRC my Dad co-signed.
There is not a hope in hell, I would co-sign for my son, to buy such a DeathTrap today, having driven and experienced the Evil Nature of that car on Polyglass GTs. Not a hope Sonny-Boy! Here's a hundred bucks; go buy you a Neon, and LIVE!
 
Well I finally had some time to get my 904 apart. This mess is now on my bench. Behold.

20180624_182516.jpg


I have not started to take apart the sub assemblies yet but it looks like my front (kickdown?) band wear material is all gone and the OD of the front (direct?) drum has started to wear pretty bad. Looks like the debris from the wear material and drum pumped through the valve body. there were pieces of the wear material and fine metal particles on the valve body/filter:

20180624_122812.jpg


20180624_122807.jpg


I will take more pictures when I break down the sub assemblies, but for now it looks like I need a full rebuild kit plus maybe a new forward drum.
 
Last edited:
First timers might be overwhelmed by all those different parts. Rebuilding a 904 is a good experience for the first time, but that much disassembly is more than I would recommend for the first timer. I wouldn't remove the governor support or rear band anchor or even the tailshaft housing. And I wouldn't disassemble the valve body either. 9 out of 10 904 trans lose third gear and have a delayed reverse. Or they slip going forward. Those two drums are the first out after the pump. And for a /6 904, I would seriously consider installing V8 drums, or at least use lower ribbed forward pressure plates as top plates on both drums. And when you assemble the pump, use a giant adjustable hose clamp to align the two sections.
 
CudaFactHackJob said:
First timers might be overwhelmed by all those different parts. Rebuilding a 904 is a good experience for the first time, but that much disassembly is more than I would recommend for the first timer. I wouldn't remove the governor support or rear band anchor or even the tailshaft housing. And I wouldn't disassemble the valve body either. 9 out of 10 904 trans lose third gear and have a delayed reverse. Or they slip going forward. Those two drums are the first out after the pump. And for a /6 904, I would seriously consider installing V8 drums, or at least use lower ribbed forward pressure plates as top plates on both drums. And when you assemble the pump, use a giant adjustable hose clamp to align the two sections.
Click to expand...

It's definitely involved but I dont think I have a choice in this case. One of the trans coolant lines on this car was twisted shut and had starved the trans of cool fluid for an unknown number of years. The heavy resulting wear on the bands and drums shed off a lot of fine metal particles that got sucked into everything including the valve body. So I'm going to take it all apart, clean, inspect, and reassemble.

This is my first time but I'm a hands on learner and like the challenge.

Also, are the V8 drums a bit sturdier? Can I use any drum from any v8 904? Im not quite sure what you mean about the ribbed pressure plates or large hose clamp on the pump, I have not gotten to those sub assemblies yet...

Thanks for the input.
 
I hardly ever find large enough particles in the valve body to hang up any valves. V8 drums have a higher ring slot so they can hold more clutches, but if you'll notice the lower forward clutch pressure plate is thinner at the edge, allowing one more plate when used at the tops. My supplier charges me $6 each. Always match the forward drum to the pump. Some only have two rings.
 
I am beginning to inspect all the parts from my 904 disassembly. See pictures below.

I know I need a master rebuild kit (clutch disks, bands, seals, o-rings, etc.) but I think I may need some new "hard" parts as well. I would appreciate anyone with some experience chiming in on what looks toast from the pics so far.

Bear with me as I am still learning component names.



20180811_153517.jpg

Kickdown band(?) looks very worn and scarred.

20180811_153342.jpg

clutch disks in forward/direct drum(?) looks slightly discolored from heat

20180811_153401.jpg

OD of direct drum(?) is very worn and scarred up.

20180811_153245.jpg



20180811_153140.jpg

OD of shell(?) is slightly worn, some scratches


20180811_153118.jpg


20180811_153042.jpg


20180811_153028.jpg

planet looks like it saw some significant wear on a thrust washer(?)

20180811_153019.jpg


20180811_152940.jpg

reverse drum shows very light wear on OD



Thought/comments appreciated as usual.
 
The most important wear parts haven't even been disassembled in the pics. You can't inspect clutches without removing them from the drum. So far it's just a band and direct (not forward) drum. The forward drum has the shaft. The direct drum sometimes called the "front" drum is mistaken for the "forward" drum. And to make matters worse, some people call it the "frontward" drum. You'll find terminology all over the board so never trust that.
 
CudaFactHackJob said:
The most important wear parts haven't even been disassembled in the pics. You can't inspect clutches without removing them from the drum. So far it's just a band and direct (not forward) drum. The forward drum has the shaft. The direct drum sometimes called the "front" drum is mistaken for the "forward" drum. And to make matters worse, some people call it the "frontward" drum. You'll find terminology all over the board so never trust that.
Click to expand...

Fair enough, I know I still need to disassembly all the sub assemblies but I plan on replacing all the clutch disks regardless of what they look. They all come in the rebuild kits I'm looking at. Component names are tricky because everyone calls them different things.

So I at least need a "kickdown band" and "direct drum" at this point?

That planetary gear looked ok? Sure looks like it saw some wear..
 
So far. Clutch clearance is critical and different manufacturers make different thickness fibers. Count the clutches. Thin smooths are forward and waffled are direct. Might be too burnt to identify. And always check endplay before you remove the pump so you have some idea how big to go oversize thrust washers. Too lose and the direct drum wobbles. And grease the center pump gear on center.
 
CudaFactHackJob said:
So far. Clutch clearance is critical and different manufacturers make different thickness fibers. Count the clutches. Thin smooths are forward and waffled are direct. Might be too burnt to identify. And always check endplay before you remove the pump so you have some idea how big to go oversize thrust washers. Too lose and the direct drum wobbles. And grease the center pump gear on center.
Click to expand...

I tried to check the endplay with a magnetic dial indicator reading on the input shaft before I took anything apart. I could not make the shaft move in or out by hand (barely moved the needle). Maybe everything is cooked together in the clutch disks?

I plan on giving everything a nice coat of transmission assembly grease, especially the gears in the pump.
 
Well, yeah, I would hope you'd lube everything but that's not exactly what I said about the pump gears. Grease them and set the pump down over the converter before you bolt the back on. The center gear will just flop around. You won't be able to insert the converter. I didn't read anything about checking the fluid level in neutral; or any mention before of the endplay. Sometimes you have to tap the shaft in. Those discs don't look like they affected the endplay. They have to be fried and chewed up. You don't have those out yet??
 
I will keep that in mind when assembling the pump, thanks for the tip.

I checked the fluid level while hot and in neutral. It was low but not dry, details in my first post on this thread.

I did try to check the endplay but was unable to move it by hand. I did not try tapping it before starting to disassemble.

I do not have the clutch assemblies apart yet, I should have it apart in a day or so.
 
Okay I saw that when I reread it. The kd rod won't affect engagement. The reason it moved after you hooked up the kd is because the fluid had a chance to cool slightly. If a tf stops pulling to or fro then just wait a few mins and you can go another couple miles. Even with the engine running while you wait for it to cool. The only question in my mind right now is what is causing the lack of endplay. Oh, you don't need a special tool or a press to pop out those snap rings and drop out the clutch stacks. You will only need something special to remove the direct retainer.
 
Forget about the end play for now. That was probably just because the large chunks of band material were stuck between the clutch packs or something.
For now, just identify how bad all the damage is. A&A Trans is one source you can check with on resurfacing the excessively worn hard parts, like that drum or even cost of replacement parts. If you have a good local supplier, like Transtar or something similar, you can check with them on cost of replacement parts.
End play can be set after everything else is figured out.
 
I rebuilt my first automatic in 1980. (I'm OLD). It was a 904 in a 73 Dart. No video, no internet, not even a book. I was lucky. Since then I've rebuilt more than a thousand Torqueflites. Now I have an ad on Craigslist rebuilding them for $400 all hard parts included. I buy cores for $50. I DO NOT repair hard parts. I throw junk parts in my junk pile for the junk man to take to the junk yard. You should look around for a V8 904 just for the HD drums. Your trans probably has three forward and three direct frictions. The V8 trans comes with four.
 
Thanks for all the info everyone, learning a lot here.


My goals for this car at this point are:

-Do a stock rebuild job on this slant 6 904 so I can put it back in the Duster and get her back on the road and have fun driving around with the stock 225 engine while I fix up other stuff on the car.

-Gather information and parts to do a v8 conversion. I already have a built 318 in the 300 hp range for this. Just need a v8 904 or 727 to put with it.


To that end, I like the idea of upgrading to better drums, clutch disk capacity, etc. but I dont see much point because Im going to put this 904 behind a stock 225 slant 6 until I am ready to go to a v8 and then I will not be able to use this slant 6 904.

As always, I'm open to thoughts/comments/ramblings...
 
Because you need a drum anyway and they're the same price; about $35; plus the kit comes with four clutches. Have you even looked in the kit and compared the clutches?
 
CudaFactHackJob said:
Because you need a drum anyway and they're the same price; about $35; plus the kit comes with four clutches. Have you even looked in the kit and compared the clutches?
Click to expand...

I have been looking at kits but have not bought one yet. I also do not have the clutch packs fully disassembled yet. Just gathering info at this point.

If the HD drums cost the same and most kits come with 4 clutches, then I agree, that's an easy upgrade.

There is a transtar near me (Houston). I was thinking of talking with them to see if they recommend a certain brand of kit and replacement drum.

Thanks for the info.
 
You must log in or register to reply here.
-

Back
Top