NV4500 main shaft preload

ahale2772

ahale2772

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Oct 27, 2011
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can anyone tell me the proper pre load or endplay on an nv main shaft?

I'm told there is a secret to doing it the right way, yet my searching has turned up nothing.

would appreciate an answer asap, as the transmission is hopefully going back together tonight.

thanks in advance
 
The factory spec is 0.002-0.006" end play, there should be shims at the rear bearing to adjust if necessary
 
but is the factory spec what keeps them together? ive heard multiple times that "setting them up the right way" is what can help keep 3rd gear from blowing apart.
 
This is a valid question that I am not 100% sure on. I have never done it on a truck with higher than stock-ish hp just the work hogs around the shop

I have always got it to .003" of endplay on the main and counter and haven't had any issues yet, just make sure everything is facing the right way like your synchros and collars and if you changed any bearings just double check your endplay cause new parts can change what you originally had.
 
No amount of end play can save third gear failures especially when pulling in that gear.
 
I do not expect it to, but if setting the transmission at 0 endplay makes it happier, then i aim to do that
 
The tranny shop told me with the Trans in neutral, one hand on the input you should be able to turn the output shaft. But it shouldn't be so tight that you couldn't hold the output with your other hand to stop it from turning.
 
depending on where you got your parts and what shims you got..... Probably the closet you can get it is .003 maybe .002 if your lucky
 
ILLINOISRAM said:
The tranny shop told me with the Trans in neutral, one hand on the input you should be able to turn the output shaft. But it shouldn't be so tight that you couldn't hold the output with your other hand to stop it from turning.
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:umno:

That is pretty vague when you have .004" to play with, and there are way too many variables to really consider this the "correct way" of doing it.
 
I think I'll be setting it as close to 0 as i can.

i went through this when building my last GRTRAG, went through a set of bearings in under 10k miles when i set it too tight.

not looking to do this one the wrong way
 
Yes anything tighter than zero will cause premature bearing failure I know first hand
 
ChuMaDD said:
:umno:

That is pretty vague when you have .004" to play with, and there are way too many variables to really consider this the "correct way" of doing it.[/

True but I never said this is the correct way to set it up. Just if you set your preload right this is what you would find so if a person was in a pinch or hurry this would give you some idea if your close. I have broke lots of Trans set up loose, tight, spec didn't matter. The one in the puller was thrown together in a last minute Trans repair and it has lasted the longest so far.
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