Gtr Rear Diff Dead Again

[confuzion]

Hey guys,

Have a 32 GTR with the stock mechanical R200 diff, in March last year the pinion bearing wore out and allowed the crown & pinion to grind gears etc

Replaced it with a 2nd hand diff and gradually a bearing noise got louder and louder and yesterday this diff is doing the exact same thing.

Could just be age from using another 15 year old diff, but i seem to be the only one in australia who has killed 2 gtr diffs?

Anyways my question to peeps is could it just be age/coincidence or could there be another factor in the 2 diffs having the same fault. eg pinion angle etc? the car has 400rwhp, is lowered slightly and has 18/255/50 wheels if that helps

Thanks in advance for any advice

[sh@un]

Hmm...you don't have really have enough power to kill a GT-R diff that has been properly serviced. I'm assuming both diffs have had adequate oil of the right grade at all times. Is your tail-shaft straight and properly balanced? If not, that would place extra strain and vibration on the pinion bearing. Do you notice vibration through the floor pan when driving?. The other possibility is that the first diff had a slight flaw in the bearing that enabled it to wear out faster than usual or that someone had had it apart at some stage and rebuilt the diff with incorrect tolerances/bearing crush (is the diff centre still the OEM part?), with the second diff-was that ever rebuilt? If so, who rebuilt it?, did they know what they where doing? If the old crown wheel and pinion where re-used, they could have been worn in such a way that it was difficult to set the correct amount of lash between the gear teeth.

[confuzion]

Cheers for the reply

Yep both diffs were being used with castrol vmx80 which i read on here was fine to use and the correct amount inside.

Tailshaft seems straight but im not sure if its balanced, there is no vibration through the car while driving however

The 2nd diff was also an OEM diff from a SAU member, it was just straight from a wrecking GTR so it could just be co-incedental that it failed the same way. This time i will get it rebuild (i have 2 to chose from!) however need to ensure this wont happen again

Cheers

[GTR32]

Cheers for the reply

Yep both diffs were being used with castrol vmx80 which i read on here was fine to use and the correct amount inside.

Tailshaft seems straight but im not sure if its balanced, there is no vibration through the car while driving however

The 2nd diff was also an OEM diff from a SAU member, it was just straight from a wrecking GTR so it could just be co-incedental that it failed the same way. This time i will get it rebuild (i have 2 to chose from!) however need to ensure this wont happen again

Cheers

<{POST_SNAPBACK}>

hey buddy how did you go?

[blind_elk]

When you disconnect the tailshaft from the diff, you are supposed to mark the relationship between the 2 bits (don't know why, but the Nissan workshop manual says to do it). Maybe that is why you killed the second one (although I would expect that you would have got vibration or something if they were mis-matched).

[MerlinTheHapyPig]

marking the tail shaft is to maintain the balance of the drivetrain. However if you swapped housings, obviously it's not balanced.

me and a friend recently killed an rx7 diff, this was apparently because when we installed the centre in the housing, the bearings on each end wern't adjusted properly and the pinion was too close to the crown wheel. The car also had a broken diff mount which contributed.

Take it to a diff specialist and get his opinion on what might have caused the problem.

[markimak]

how much for a GTR rear diff? good condition.

[gts4diehard]

hey, just a comment on your diff oil, isnt that oil just for gearboxes?

because thats what I used to use in my GTS4's gearbox, the gts4's had a different type of lsd which used lsd oil

shouldn't you be using some sort of lsd oil?

check out link below. I would still check the lsd oil, to make sure its up to spec, but vmx 80 is for the gearbox.

http://www.datateck.com.au/lube/castr_au/d...e=45&Model=1316

Stephen

[markimak]

LSX 90 is for LSD's transfer case and gear oil can be either..

[confuzion]

Hey guys,

Thanks for the replies,

Ive been driving it on/off last couple of weeks (been avoiding due to the loud whine and grind of gears) and last night was the first time i flicked it to rwd mode since the diff started making this noise - absolute silence. How can that be?

4wd mode - whine noise and gear grind when you take foot of throttle

rwd mode - instantly silent and smooth as

back to 4wd - whine noise and gear grind

back to rwd - silent and smooth

So does this mean its not the diff after all or is there something else when 4wd is activated that is broken?

CHeers

[markimak]

bleed ur attesa ETS system before u do anything else. sounds weird never heard of that.. deffently a prob with ur ETS. bleed it. change auto in trans case and just diagnose wat is broken. is urs a later model GTR? if so u got a different transfer case set up. u might not have oil in ur case?

[confuzion]

bleed ur attesa ETS system before u do anything else. sounds weird never heard of that.. deffently a prob with ur ETS. bleed it. change auto in trans case and just diagnose wat is broken. is urs a later model GTR? if so u got a different transfer case set up. u might not have oil in ur case?

Thanks mate,

Yeah ive never heard of it either - I will do as suggested cheers!

ps. Mine is an 89 but im not sure if it has a newer or older box/case? Probably normal 89 one...

[confuzion]

Hey guys,

Just an update, have checked all levels of fluids and they are all full, have bled the ETS system as per service manual and no go, still whines in 4wd, but perfect silent in rwd mode..

SO im guessing it is a mechanical fault in the transfer case, like a bearing or something?