# Rebuilding a GTR rear diff....



## tarmac terror (Jul 16, 2003)

OK, now that I have secured my new LSD, I am going to have to strip it all down and change over the CWP for my GTS-4 items.
Looking at the CW, there doesn't seem to be any method of adjusting the L-R movement as seen in this pic..









similarly, the GTS-4 pinion I have would appear to be fixed once its all secured in place. which leads me to the following questions..

1. IS the CWP meshing adjustable?
2. Do I really need to take it to a specialist to get set up?

From what I can see, the CWP interaction seems fixed so IS it a case of just whipping the std GTR stuff out and rebuilding with the GTS-4 CWP?

Having had experience in rebuilding Ford RWD diffs, the pinion has a crush spacer which determines the meshing of it with the CW. The GTR pinion spacer does not appear to be a crush item and so would, logically make the rebuilding of a diff an easily repeatable job.

Anyone...

TT


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## Sub Boy (Jan 28, 2008)

Setting backlash is a tricky job.....I just took mine to a specialist, there's lots of things I'm prepared to do myself on my car, this wasn't one of them.


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## tarmac terror (Jul 16, 2003)

LOL...yes I've gone through a couple of Ford diffs in the past thinking I could 'wing it'. That said, the Ford diff actually had some adjustability, while the GTR diff seems pretty fixed in its meshing.
The way I see it is that once the CW is on the LSD unit, bearings on and it all placed in the diff casing with the caps tightened up the only thing which could possibly move is the pinion. Again, from what I see, the pinion isnt adjustable for fore-aft movement either once the races and the spacer are tightened up..

Puzzling..

TT


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## lightspeed (Jul 11, 2002)

If you read the workshop manual first you will see that it is all done with shims rather than crush tubes or threaded adjustment. 

Not too hard a job unless you lose the original shims and don't have a good start point.


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## ANDY H (Mar 17, 2005)

It's shimmed behind the bearings to ajust the side to side movement! 
The pinion has to be correct as does the bearing preload and the mesh between the crown wheel and pinion ( tooth mesh) you'll need to blue it!!
And while you doing all this you will need to have the correct back lash and bearing preload!
And if any of this is out you'll eat the crown wheel in know time!
Take a look at the manual it gives you all the specs.


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## GT-R Glenn (Nov 9, 2002)

Use the 4 housing, just swap the slippery unit.
Its already setup


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## AlexJ (Apr 3, 2003)

What did you do about this in the end TT?


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## arnout (Oct 29, 2003)

shims?


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## tarmac terror (Jul 16, 2003)

Well, I stripped it and swapped out the std LSD with the Nismo unit.

I noticed the shims on either side and built it back up. I have to admit that, as it's not a pressing priority it has languished in the garage waiting for me to be motivated to set it up per the book. If I'm honest, just replacing the shims as they were originally, the meshing looks pretty good. Obvioulsy thats not really good enough and I'll have to do it properly and check preload as well.

Sorry thats not a final answer I'm afraid!! If I can be bothered, I'll perhaps make an attempt this weekend!! 

TT


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## AlexJ (Apr 3, 2003)

Lol well i'm in no position to judge, my garage is full of half finished projects.

Surely if you just changed the diff internals, the C&P and bearings aren't effected so the lash and mesh aren't changed?


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## tarmac terror (Jul 16, 2003)

Sorry, I should have added that I also rebuilt the diff with GTS-4 CW&P. 

TT


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