R33 Gtr Rear Diff

[tommis85]

Hi peeps,

Some of you may be aware of that I've been driving around with the front prop shaft out because of my shagged from diff (new front diff has finally arrived so will have it in soon)...however, in the mean time I've noticed something peculiar with the REAR diff.

The past week of wet weather has made a mess of my dirt/grass driveway and when I go to drive up to the rear shed the car will start to spin on just one rear wheel. It can no longer shift torque to the front because of the missing shaft etc so it just lights up on one wheel and gets bogged down.

My question to you guys is, is this normal? Is a R33 GTR meant to light up on both rears or will it select one like a normal differential? I've never had diff issues before so am not up to speed with how all the different ones work in the GTRs...all I do know is that the front one is a plain LSD and differs from the rear etc.

I've also noticed that in the past when it did have the front connected it would feel rather odd at the rear when full throttle...as if one side was putting down more power than the other side.....a kinda twisting of the car.

I'm thinking that the torque split had effectively masked a problem with the rear diff?

Any help would be greatly appreciated....thanks guys!

[tommis85]

**double post if anyone wants to delete it**

[R31Nismoid]

VSPEC or not?

If non-vspec, just get it rebuilt or put a Nismo 1.5 GT pro into it. Best mod i reckon i did to the GTR, makes it MUCH more tail happy, could 4 wheel power slide it much easier which on tighter motorkhana stuff meant i was noticeably faster.

If v-spec, and therefore A-LSD... read this... (its an expensive trip):

http://www.skylinesaustralia.com/forums/topic/399722-change-diff-from-a-lsd-to-mechanical/

[tommis85]

VSPEC or not?

If non-vspec, just get it rebuilt or put a Nismo 1.5 GT pro into it. Best mod i reckon i did to the GTR, makes it MUCH more tail happy, could 4 wheel power slide it much easier which on tighter motorkhana stuff meant i was noticeably faster.

If v-spec, and therefore A-LSD... read this... (its an expensive trip):

http://www.skylinesa...-to-mechanical/

Thanks for that. Nah mines just a standard GTR. So what would be going wrong with my diff if it's so easily lighting up on just one wheel? Once upon a time I did know what diffs are in what but right now I can't quite remember what's in a 33 GTR (and also late R32 etc). I'm assuming it's not a full LSD? Hypnoid something?

[R31Nismoid]

It's 15 years old, its just shagged.

Rebuild the stock center or put a stronger Nismo one in. Nismo ones you can also adjust how tight they lock.

[GTSBoy]

Of course it is supposed to be a full mechanical LSD in the rear of a GTR*. And of course it should not behave like yours is behaving. And that suggests that yours is completely stuffed in some way. Probably just worn. Although that does take some effort to achieve.

Nismoid's suggestion above makes the most sense. It is also possible to rebuild the centre you have.

*non V-Spec that is.

--edit-- beaten.

Edited July 22, 2012 by GTSBoy

[tommis85]

Thanks for the clarification gents....muchly appreciated! Yes well I was under the assumption too that it is an LSD, just not as complicated as the A-LSD in the Vspec models where it splits torque from left to right etc.

Ok, well I guess I'll go suss out some costs for those couple options. This is probably why my car is also pulling to the left even though I've only just had it aligned....it's definitely getting more power to one wheel and for all I know it's only driving one wheel full stop

1-wheel drive GTR....now I know how commodore drivers feel

Edited July 22, 2012 by tommis85

[GTSBoy]

It would be unusual if you'd managed to snap a half shaft or something like that. Definitely get it to a mechanic.

It's >$1200 to buy a brand new diff centre (like the Nismo unit), and it can be almost any amount of money to rebuild your original one. Best to know what is wrong first.

[tommis85]

It would be unusual if you'd managed to snap a half shaft or something like that. Definitely get it to a mechanic.

It's >$1200 to buy a brand new diff centre (like the Nismo unit), and it can be almost any amount of money to rebuild your original one. Best to know what is wrong first.

Yeh that shouldn't be the case. It could be that it's just badly worn. Now when I think of it, even 3 years ago at QR Sprints it did funny things on the corners past the big dipper....it would always light up a bit on the inside wheel rather than light up both and step out.

I have been doing some reading on diff oils too....how much would the couple different grades of diff oil affect how limited the slip is? Can you have oil in it that would make it become an open diff? Or would you only ever vary the amount of slip but never get rid of it all together??

I'm running that LXD90 straight 90 in it right now because I didn't have anything else.

[GTSBoy]

Yeah, for an mech LSD, you MUSt use LSD specific oil in it. Other gear oils have friction modifiers etc in them that kind of interfere with the whole LSD thing.

[R31Nismoid]

LSX90 is the oil to use.

You can add a friction modifier if you want to reduce how "harsh" the bite of the diff is and/or the clunking.

And no, don't use different oils. It's all controlled by the clutch plates and gears in the diff.

As stated - get it pulled apart and see what is wrong first.

[tommis85]

Ok, so I've just been out to a gearbox place where we had a talk about the 2 diffs. Also received a mint front diff center from Xklaba on here but I'll have to get some new front/rear and side carrier bearings along with their respective seals. It would be unwise to reuse the current ones or? Apparently they need to be removed and reinstalled - a process that damages them? (apologies for my lack of knowledge in this area)

So, that there would come to about $550 labour plus the coast of bearings and seals.

But, because of the money involved I've decided to rebuild the rear diff first as that makes much more sense and just leave the front disconnected for now. The gearbox fella agreed that it's probably just worn out one side worth of clutch pack plates which is why it's feeding the power to just one wheel.

Looks like I'm up for a Nismo unit hey? Unless one was to go down the slightly risky second hand path and swap it out for one that hopefully is in better condition

[Piggaz]

Looks like I'm up for a Nismo unit hey? Unless one was to go down the slightly risky second hand path and swap it out for one that hopefully is in better condition

Why bother going to all that effort for an unknown result. Bite the bullet!

[tommis85]

Why bother going to all that effort for an unknown result. Bite the bullet!

You're right Piggaz. I'm merely just looking at options because this whole show is already having it's tole on the hip pocket.

So apart from places like RHD....where can I get these LSD upgrades from? Also, on here's probably also the best place to ask where I can obtain the bearings and seals needed for swapping out the front diff center as I've been told that it's not wise to re-use the old ones as they get damaged when removing them.

[tricstar]

Man your hip pocket better brace itself ! !

just did the Nismo in the rear $$ but also did wheel bearings and boots while everything was apart ..... holy $$$4k but that was changing from an A-LSD, at least you can use your diff housing and axles.

yeah RHD was as good as any to buy from.

[tommis85]

Man your hip pocket better brace itself ! !

just did the Nismo in the rear $$ but also did wheel bearings and boots while everything was apart ..... holy $$$4k but that was changing from an A-LSD, at least you can use your diff housing and axles.

yeah RHD was as good as any to buy from.

Gees man, yeh my budget for all this crap is fast running out PLUS (now this makes it worse) I've also been thinking about selling the car for a while now. So I don't really want to spend big on upgrades - rather just want to replace broken parts with good 2nd hand gear like with the front diff. Damn money pits!

Sounds like you're pretty happy with your new setup tho

[tommis85]

Hey fellas so I've gotten on to Nissan for some bearings and seals for the pinion and shafts and it comes to around $500. Now, I was just wondering if this is it or if I can get these seals and bearings for a bit cheaper in Australia? At first I was going to try to re-use my old bearings and seals but my gearbox guy advised against it and also said that the bearings usually get damaged in the removal process (something I'm a bit uncertain about). Also, the workshop manual states that the seals should be replaced anyway..

Can anyone help with parts? Or am I on the right track with Nissan/Japan?

[Moodles2]

RHDJapan has alot of genuine Nissan skyline gear so you should be able to find what your after for half the price. If you need it ASAP, try Kudos motorsports, sponsor on this board.

[R31Nismoid]

Yeah Kudos seems to have some amazing pricing on Nissan OEM stuff, always have a check there if you need something

[tommis85]

RHDJapan has alot of genuine Nissan skyline gear so you should be able to find what your after for half the price. If you need it ASAP, try Kudos motorsports, sponsor on this board.

Thanks, I'll jump on their site and have a look. It would be good to pay a bit less than what Nissan wants haha