1965 904A modification.

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circlepilot

circlepilot

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(The title should be A904)
Well I'm doing it, but not without help. I'm modifying my 1965 A904 by installing a post 1968, non-lock-up, 27 spline input shaft, pump and clutch housing. Why? Torque converter selections. The pre-68 904s input shafts will not allow you to use available, higher stall converters, unless you have one (very expensive) custom made, then you are stuck to just that one, until you have it rebuilt or another one made. Why not just get a 68 or above 904? I don't want to modify the car,(cut a hole) in my 1965 Barracuda, 225. I want to keep the cable shift, shifter and related linkage. I'm "hot rodding" the slant six (with all kinds of bells and whistles) and plan on racing it; I need the higher stall converter, also my crank shaft register has been opened up by my machinist to accommodate the bigger converter. In all of the years working on cars, building engines etc., I have never tore down an automatic transmission. So this is also a learning exercise. I've have gotten guidance, advice and tons of information from members here on the forum and I have manuals. I got my parts off of the net and tonight I started the tear down and insured that my parts are going to work. There is a complete overhaul kit and a shift kit in works also.

904 mod.jpg
 
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You've got this, looks like you're well on your way to success! 65'
 
Carburetor kits are "complete", but transmission kits are not. Did you measure the end play before you took it apart?
 
CudaFactHackJob said:
Carburetor kits are "complete", but transmission kits are not. Did you measure the end play before you took it apart?
Click to expand...
I haven't completely disassembled it yet. Just pulled the valve body, pump, clutch drum and input shaft. (mainly to check and see if the shaft, pump and clutch drum that I have, were going to work.) Referring to end play...are you talking about the fore and aft play of the input shaft? If so, no. What guidance I've had and the service manual and videos I have viewed, did not mention it. (unless I skipped over it) Before I go any further...I'm waiting on a book (should be here tomorrow) dedicated to the overhaul of Torque-Flites. I bet that measurement will be covered. Thanks for the "heads up."
s-l500.jpg
 
There are some good YouTube videos out there too. Do a search, you'll be surprised at what you find. 65'
 
The book from Tom Hand is good, but be aware that he is mostly describing a later model 904. I rebuilt my 69 904 and always used the specs out of the 69 shop manual. I suggest to use the book from Tom H. as a general manual for dissembling, testing and assembling, but when it comes to washer thickness, number of clutches and other specs, refer to the original shop manual. W.I.T. for example has a lot of parts for pre 70 904 transmissions, but you need to search with the part number.
Happy wrenching,
Wolfgang
 
Plymouth 65 said:
There are some good YouTube videos out there too. Do a search, you'll be surprised at what you find. 65'
Click to expand...
I have probably watched dozens of torque-flite videos. A lot of differen't ways of doing things. Got a lot of good information. However, I have encountered a problem, that I'm researching now. The piston that goes in the input shaft clutch drum (piston retainer, original part) is too small to fit the 1968-70 clutch drum (piston retainer) I got off of the net. The 27 spine shaft fit just fine.

904 piston.jpg
 
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I feared that you will run into fitment issues. The 904 internals changed a lot over the years. Parts look similar but if you measure them, you will notice differences. If you don't have a donor 904 trans from the same year and model, lot of parts don't interchange. I think a custom made converter will save you in the end nerves and money. Precision of New Hampton for example makes excellent converters, has great customer service and prices are fair. They can also upgrade or rebuild your original converter.
 
Just to give you a number:
I spent around 490$ just on parts for my transmission rebuilt - total stock - no performance parts, just a deeper oilpan. The 904 universal crap rebuilt kit contained mostly wrong parts. Apart from professional cleaning of transmission parts, I rebuild the transmission all by myself. A good converter won't cost much more and should last. If you want to make it right, take your time and don't save on transmission overhaul and converter.
 
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I check the endplay before I take it apart so that I know how much more thrust washer I need to tighten it up to around .020. Most of the times, I reassemble TFs with all the original hard parts and thrust washers. Maybe a thicker button one between the shafts, or add to the pump. Sometimes I get lucky and only have to put it together once. But it's usually three times. You can avoid most problems by keeping the input shaft, forward drum, and pump all together. By all means, get rid of that old converter. Use V8 guts because the drums have the retainer ring groove cut higher to fit in more clutches. Often you can use a forward clutch bottom ridged plate as the top plate to gain one more friction in both drums...3 to 4...but not 4 to 5; usually. My trans parts supplier only charges $6 for each forward clutch bottom ridged plate.
 
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