I think your talking about the very thin anti fretting ring below the center support. They used this to help prevent wear to case under load. The newer center support is thinner the allow the ring to be used.......it can be retro fitted into an earlier case as long as the correct center support is used......measure the lug thickness to verify
I don't race, and I only shift hard on occasion with my 4L80e trans. I believe the solution is to have another solid drive shaft made or have the original unit welded. One or two guys on the forum actually race their Rivs and I understand both solutions have been done.
I will look into this, I appreciate you bringing it up! I recently talked with my local driveline shop and the good part of that conversation was the man was trained by his old timer father who used to run the business and brought up the whole driveshaft phase thing. So I know I am in good hands by having him go over it, but now after listening to you I will ask about performance solutions.
Your description of the ring sounds much better than mine. But yes, that is the ring I am talking about. I will check some measurements but for educational purposes, if I am using the 70 center support in a 69 case then I should be able to use the anti fretting ring? And if I use the 69 center support in the 69 case then it technically shouldn't fit? This isn't a race trans, I just need it to hold up to my heavy foot in my Riv with a mildly built 464. Thanks!
If I recall center supports to be used without the fretting ring are about .370 thick, to be used with ate about .330 thick. These can not be mixed or matched but can be swapped out if using the ring when needed. If you add the ring to the early support the the top snap ring wont fit right......if you forget it when it should be there you will have too much support movement
Your measurements are absolutely correct regarding the center supports and the fretting ring from the '70 is right around .042". Is one center support version preferred over the other version or is it use what you got?
I've used both. But there had to be a reason the change was made. It certainly wasn't cheaper or easier
I'll will just plan on using the 1970 support with the ring in the 69 case unless something throws a wrench in my plan. Thanks again Ben!
That ring prevents wear into the case, which will be obvious in a high mileage case not using it. The case dimensions did not change when it was added, so the thinner center support and ring can be swapped in as a set into an older transmission. I guess the older center support could be machined to make room for adding the ring, do not know if anyone ever did that. Bruce Roe
Thanks for the info and confirmation of the swap Bruce, I appreciate it! This project and rebuild are a big learning curve for me.
I have made it far enough through the assembly process to check my output side end play. I have replaced all bushings, bearings, thrust washers and rollerized the output shaft with a Sonnax kit which includes the no walk bushing as well. Remember, I am using a 1969 case with 1970 internals if this matters, but I'm guessing not. Before disassembly of both transmissions I got no noticeable output end play on either transmission but I did get some input end play on both. I assembled the transmission all the way to and including the first snap ring above the center support and checked my output end play. Results are nothing detectable. The snap ring went in fine as well. Am I doing something wrong or missing something? Should the trans be in a certain position to correctly check end plays? I am assembling the trans on a bench and also using the plywood on bucket bench method also. The Sonnax bearing is right around .140 and I have a .010 selectable in there. The 3 tang and 4 tab washer in the 1969 trans was aroung .145" and around .149" in the 1970. Thanks!
To measure output shaft end play.......flip it over with the output shaft facing up and use a daily indicator.....you need to pull up and down.......there is some weight in there so it does take some force..........and your sun gear shaft may fall out.. .007-.019 is what your looking for Set the front .002-.005 greater than rear setting
The 69 center support or the 70 center support with the ring are each the same total thickness, can be swapped as a set. The ring avoids case wear, which can be seen on earlier high mile TH400s and can be damaging. All mine are converted for the ring set. Bruce Roe
I will be utilizing the '70 center support and ring, this way I won't have a case wear issue down the road. Thanks Bruce!
So here is my current situation, trans is going together pretty well. Right now I am waiting on a couple of thinner selective shims for under the pump to gain some end play back. I installed a Sonnax extreme duty forward clutch hub kit with the torrington bearing and that ate up some of the end play. I should be able to get back into spec with the .073" or .084" selective under the pump. Currently there is a .095" selective in there. So while I am waiting for my washers to show up I figured I would stay productive and replace the tail shaft housing bushing and seal. Only problem is that the bushing and seal in the kit are too big to fit. I then compared to a different TH400 and same thing. Has this happened to anyone or do you have any ideas on what I need to make this work? Thanks all!
Solution found, there is a company I stumbled across on eBay that sells the small bushing and seal combo. A little pricey but I guess that is just the Riviera tax I gotta pay! http://www.ebay.com/itm/302863037677