Transmission Rebuilding 101

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GotDart

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Excellent idea Greg. This is about the only thing on a car that I HAVEN'T rebuilt in all my years of shade tree wrenching. I've done valve bodies, seals, and shift kits, but never had the balls to really dig into an auto tranny. :)
 
A great book on the subject is " Torqueflite A-727 Transmission handbook " by Carl. H Munroe.
I just finished reading it and it seems very good , and i have heard great things about it! :)


Heres a link to Moparts.org and their tech archive on Auto-Trans:
http://www.moparts.com/Tech/Archive/auto.html
 
Chrippa said:
A great book on the subject is " Torqueflite A-727 Transmission handbook " by Carl. H Munroe.
I just finished reading it and it seems very good , and i have heard great things about it! :)


That is a great book. I bought one too. It's the most in depth (but easy to read) Torqueflite manual I've found.
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I've seen that book. Does it cover the 904 at all? Are the 727 and 904 similar enough that the information in the book is relevant?
 
GotDart said:
I've seen that book. Does it cover the 904 at all? Are the 727 and 904 similar enough that the information in the book is relevant?
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I dont really know the difference between the 904 and 727, only that the 904 is suposebly weaker ?
There is nothing indicates that it covers the 904, but are there any parts interchange between 904 and 727 ? Someone must know :)
 
Chrippa said:
are there any parts interchange between 904 and 727 ? Someone must know :)
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I have read where people used 904 'guts' in a 727 case. I have also read that you can use a 727 valve body in a 904. It would be interesting to see a complete list of parts that can interchange, but that's not the point of this thread.

I bought an ATSG service manual that does cover both 904 and 727 off ebay for $15. I guess it wouldn't hurt to go ahead and pick up the 727 Handbook by Munroe, it's only $11 from Amazon.com. Anybody know of any other printed reference materials or maybe a video?

Here are a couple more websites with some good info.

A999 rebuild article - I wish the author would finish it. Some great photos, and there is a tip on how to remove the pump without a slide-hammer.

AllPar tech article
 
ok has anybody changed the planetary gears in their transmision to a lower set? if so how much of a difference did it make? i thinking about changeing the 1st and 2nd gear in mine to, 2.77 first & 1.57 second....any thoughts?
 
7demon2 said:
ok has anybody changed the planetary gears in their transmision to a lower set? if so how much of a difference did it make? i thinking about changeing the 1st and 2nd gear in mine to, 2.77 first & 1.57 second....any thoughts?
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I haven't, but the Moparts link that Chrippa posted had a discussion about this.
904 Low First Gear Set
 
thanks GotDart....it seems like it is a take it or leave it thing....humm? well i only have a 3.23 sure grip, and don't want to change it. i figured that it will give me a little more bottom end. top end isn't a problem......jury is still out, but closer to a decision!
 
Great thread!!!!!!!!!!! I was thinking about rebuilding mine this winter. I also picked up Torqueflite A-727 Transmission handbook about a month ago and is an EXCELLENT resource!!!
 
The 727 and 904 are very similiar transmissions. I have also read that you can use 904 guts in a 727 case but not sure why you would want too since the 904 case is lighter. Maybe cause the 727 case is stronger???

Like I've heard it described before "the 904 is just a baby 727".

Got Dart I also bought an ATSG manual first. Then I ran accross the manual by Munroe. The ATSG will show you how to rebuild a stock 727. Munroe's manual goes WAAAY beyond that. It totally describes how the Torqueflite works and has seperate chapters on building a stock one, one for the street/strip, or a full race trans. Everything is detailed. Just for the record I'm not knocking the ATSG manual just saying how much better Munroe's is.
 
GotDart said:
What I've heard is the 727 is a 904 on steroids. :dontknow:
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Well isnt that about the same thing as 904 being a baby 727 :D :hello2:

Heres a thread from the Dodge Challenger MB on installing a overdrive from Gear Vendors in a Chally.

Part 1
Part 2
Part 3


//Chrippa
 
Chrippa said:
Well isnt that about the same thing as 904 being a baby 727 :D :hello2:

Heres a thread from the Dodge Challenger MB on installing a overdrive from Gear Vendors in a Chally.

Part 1
Part 2
Part 3


//Chrippa
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hey Chrippa we can't log in to the dodge challenger message board.....need a password!
 
Be very careful what you read. Very few, if any, parts interchange between the 904 & 727. The only exception that I know of is the valve body-BUT it must be the same year. Got bitten on that one! Also, check very carefully on shift kit instructions. If it says drill a hole in the case at the accumilator, read the year model and be very sure you have the right year model. Another bite- big one. Trashed a good 727 case. Pay close attention to clearances. End play and clutch clearance. Your old seal(clutch piston) and new ones may not be identical(smaller lips). There is only one spot each one will fit in. They are different diameters. One tip on piston seals,if I can accurately describe it, is to install the new seal on the piston. Clean the piston first. Take the old seal and turn it wrong side out and stretch it over the new one. That will shrink the lip diameter so it will slip into the bore easier. While you are cleaning/inspecting the rest of the assembly should be enough time(at least 30 mins). If it does not slip in easily use the edge of a feeler guage to tuck it in. Be sure there are no burrs on the edges. Patience is key here. Use plenty of lube throughout. Newspapers make good table cloths for the work bench and are easy cleanup. Make sure to lube the front pump gears with a heavier lube. If you don't have assembly lube for AT's vaseline will work aok.

Hope that helps. Good luck!
 
a good thing to have is some real automatic transmision asembly lube i cant remember the brand i use but its a white plastic container with black and blue text on it, that stuff is lots more slippery than anything else i have tried and makes it lots easier to get all the seals to slip in nicely!
also lots of patience is usefull! (think twise do it once)

i think dose guys runnig 904 internals in 727cases are doing so becuase they want less power loss and as we all know no 904 cases fits bigblocks so those two things maych each other!
corect me if iam wrong but i think AMC used 727 gearboxes with 904 internals, so i gues it could be posible to take those internals and put in a 727mopar bigblock case but this is not guaranteed to work just a thougnt i have been thinking some of..
 
7demon2 said:
hey Chrippa we can't log in to the dodge challenger message board.....need a password!
Click to expand...

Sorry didnt think of that :)

Just register on the board and you can read it :)

Doesnt someone have all the info on what parts interchange and those who dont ? Would be cool if what Duster340 says is right about AMC 727.
 
Some excellent tips dartjack. Thanks!

The AllPar tech article I posted a link to has a lot of historical info as well as theory of operation. It also discusses similarities and differences between the various Torquflite models. Worth a read for sure. And it does tend to confirm the 904 guts in a 727 case...

The 998 was a 904 built inside a 727 case. AMC used the same transmission case behind all its V8s but only used 727 internals behind the 401.
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Any other tips or tricks for rebuilding these slushboxes?
 
Jeep did not use 727 with 904 guts. Jeep by need would use the heaviest available unit. A 998/999 is a 904 with an extra clutch plate for more torque capacity.
 
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