1990 700R4 3-4 clutch pack clearance with 8 frictions and 7 steels ?

[Burb restorer]

Greetings to all fellow square body owners!! I am at a stand still, I seem to keep getting different clearance numbers on the proper 3-4 clutch pack set up WITH 8 frictions and 7 steels. I know the 3-4 clutch pack set up can be a real problem area so I need this to be spot on. I'm using the "HEG" type of frictions since this transmission is going into a 1987 Suburban 4X4. I really need someone who has done this with excellent results as I am extremely adamant on building this and NOT wanting to go back into it for MANY years down the road. I am currently running around .044 clearance. The ATSG manuals (Rebuild AND updated book) only speaks of 5 frictions and 6 frictions. As a last resort, I ventured out to YouTube (YOU guessed it) and one person said this 3-4 clutch pack clearance is "ok". I air checked it several times and used a dial indicator to get a more accurate reading. Many thanks to all who wish to add some input (No pun intended) on this clutch pack set up. Keep em' rolling........................

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[Matt69olds]

The rule of thumb is .010 per friction, however some builders like the 3-4 a little tighter than that. Personally, I’d want a little more than what you have, but as long as you reinstall the load release springs I’m guessing it will work just fine.

 

[Burb restorer]

Thanks Matt69olds. I just wonder why one book says to reinstall the load release springs and another book says most builders leave them out. The LAST person who built this left them out and the 3-4 clutches were burnt. It is a little confusing but I am still looking for a happy medium. It will NOT be used for racing or high performance so I am sure that has something to do with it. I just found out late this afternoon I am supposed to run 9 clutches and 8 frictions with the HEG frictions and "TRY" to obtain a minimum of .025. That seems just a tad tight but I am still working on it. Back to the work bench tomorrow.

 

[Burb restorer]

LATEST UPDATE: After conferring with the company who sold me the rebuild kit, I am advised to install 9 frictions and 8 steels AND set the clutch pack at .025-.040 clearance. I did install the 9 frictions and 8 steels (DID not use either of the two extra thick steels) and used the original clutch backing Selective plate and the "NEW" .062 snap ring in the kit. I air tested it and with a dial indicator, I am running .027 clearance. I don't rebuild transmissions every day but has anybody else run this set up on a regular 4WD truck before? I will NOT be racing or rock crawling butI just want a durable heavy duty set up and I am running an accessory transmission cooler due to the Florida heat.

 

[Matt69olds]

The load release springs physically ensure clutch release. I’m guessing people started leaving them out years ago trying to figure out why the 3-4 clutches are always cooked. If you think about it, it takes very little pressure to overcome the tension of the load springs. Also, GM is always looking to save money. If the springs weren’t needed, rest assured GM wouldn’t spend the money putting them in.