Right now my transmission drivetrain is together with .010 rear endplay and .015 front endplay.


i can change a rear shim and sand down a pump shim to get .005 rear and .010 front.

Is it worth tearing it apart to tighten it up? What difference does it make? I know i am within the book spec as is, but i want your opinions. This is a performance application, with the rear rollerized.

 

Leave the rear section end-play as is.
The only time to get away with tighter end-play is if all thrust surfaces have torrington bearings, not thrust washers.
Even then... bearing life will be better if each bearing location has 0.002" to 0.003" clearance at every thrust location.
Tighter can shorten bearing life as oil can not pass through the bearing as readily.

As far as front end-play... is 0.015" just the front section; meaning the rear section is pre-loaded upwards?
Or is 0.015" total end-play with the rear section down, not pre-loaded?

 

The only things i have rollerized is the forward hub and the output shaft.

.015 is with the endplay preloaded.

when i preload the rear carrier with the screwdriver the input shaft moves .010. When i lift it up, i first take the snap ring clearance up, then i lift harder and get .015 with the .075 pump shim in.

 

It is times like this when I really wish that I could physically be there to feel and measure the transmission myself.
I can not comfortable say what is good or not from the videos with out feeling things myself.
Sorry, someone else may feel comfortable enough to say otherwise.

 

i will gladly video chat with ya at some point if you would like. I am confident in the measurements because they are repeatable. I accidentally put the .060 shim in there instead of the .075, and got .030 clearance. I was puzzled until i realized what i had done. I popped the .075 in and got .015.

 

Why did you start a new thread? Same issue, should have keep the old one going.

 

there was a lot of previous measurements and other information that is now irrelevant. This was my attempt to consolidate info and make it a little less confusing. Hopefully that worked.

 

What i basically want to know, is what do i GAIN from tightening up .005 on both ends? What is the benefit? That will help me decide whether or not to strip the trans down again.

 

I would personally leave the rear section as is... and not reduce rear section end-play.

Now in regard to the front section... I am hesitant to make a recommendation, because I am not sure that you have a true measurement.

From what I have ONLY been able to view on video and not feel... I would leave things as they are.

 

The other videos are outdated. Assuming the measurements are correct, what is the benefit?

i am literally about to remove the forward drum and reach the point of no return. I sanded the .090 to .080 and test fit. .010 front endplay now compared to .015 that the .075 shim gave me.

my gloves are on as i type this...

 

Alright... I do not really want to get into the physics of this in the form of a long typed out explanation.
It would take too long to get into Theory.

But... I will summarize...
Reducing the end-play, limits the amount of lateral thrust, that the gear-sets and shafts can travel.
This in theory should prolong the life of the components when an ideal range of end-play is established.

Excessive end-play can permit excessive thrust forces to prematurely cause wear and tear.
Insufficient end-play can prevent enough lateral movement, and enough space for thermal expansion... In turn, also causing premature wear and tear.

Reducing end-play is not necessarily a benefit at all...
There is a specified range of end-play for proper operation of the transmission.

Too little end-play is NO-good... AND too much end-play is NO-good.
Your rear-section is in the proper range of desired end-play; and there is really no actual benefit to reducing it.

Now generally speaking; if all the thrust surfaces had Torrington bearings... The unit could get away with less end-play.
I actually do not like going this route.

When I build a 4L80E with ALL torrington bearings and no thrust washers...
I add 0.002" to 0.003" of end-play for every bearing.

Through use of an Engine-Transmission run-stand (What people often refer to as a Transmission Dynomometer) I find less end-play than that results in unnecessary/ unwanted wear and tear.
I personally find that 0.001" to 0.0015" of clearance for each side of the torrington bearings, to be ideal for the ATF to properly lubricate the rollers inside the bearings and support the thrust components of the transmission.

In the configuration shown in the photo below (of the rear section thrust components and torrington bearings)...

There are 4 torrington bearings in the rear section; when no thrust washers are used.
I machine components to a dimension, where I can replace a thrust washer with a torrington bearing.
So in this situation; 0.003" per bearing; multiplied by the 4 bearings...
I personally set rear section thrust to 0.012".

I hope this was made clear enough.

 

clear for sure. But too late haha. I spazzed out and redid everything. The drivetrain is finally complete and i ended with .005 and .009 endplay. I really appreciate the help going through this. I can say i can put one of these together with no thought at this point. I have taken mine apart literally 80-90 times being OCD about everything. Again thank you.