Changed Gearbox + Diff oil..

[LSky]

Last week I changed my gearbox and rear (only) diff oils, I used Silkolene Silktran Syn5 for both, gearbox seems fine, but now I'm getting what I can only describe as a "judder" at very low speeds whilst turning, apart from this all else seems OK. My assumption and feeling is the rear diff is not liking the change, prior to the oil changes all was fine. I'm glad at this point I didn't do the front diff and transfer box oil changes, that would have added more questions to the equation!

Maybe I should have used a Slip diff oil such as Silkolene BOA 90LS, although after research I gathered that the oil I used should be OK for the rear diff.

Thought's Anyone?

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[LSky]

Bttt
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[gtr mart]

pmthis thread to oilman. They are very knowledgeable on oils and may be able to give you guidance on the oil you chose and the symptoms you are seeing.

If he suggests the oil is fine then I guess its something else.

Are you certain you filled the boxes up? could they be low?

[LSky]

Thanks for the reply Mart.

I've checked the levels and their OK. A friend of mine said the standard GTR diff is a viscous LSD type and the oil I used may be too thick, I'm going to look into that possibility. I'll PM Oilman as you suggested and see if he can offer any advice.

Cheers.

[oilman]

This oil should be perfectly fine for the LSD. It's approved for road and competition LSD's so I'm sure the oil is not the problem.

The book specifies 75w-90 GL5 and or 90 GL5 which is also covered by 75w-90.

I'm not entirely sure what the judder at low speeds is but it would seem odd that this only occurs at low speeds or is that just where it's noticeable?

The oil is also not too thick, 140 would be but a 90 gear oil is a 90 gear oil.

Cheers
Simon

[LSky]

Thanks for the reply simon, BTW have PM'd you aswell, yes I understood that Silktran was fine for the diff, I did my research before I used it and it came recommended. By judder its feels as if something in the transmission is holding me back together with a vibration through the car, when doing slow speeds when parking and the like. Its strange and a little disconcerting and I hope no damage is being caused. IT was not noticeable before I did the oil changes.

[oilman]

It sounds strange to me to and I'm baffled as to what it may be. What was the old oil like when it came out? Was there any trace of particles in it?

I'll call the boffins tomorrow and see what they have to say on it.

Cheers
Simon

[LSky]

Nothing in the oil that came out of the diff, in fact it looked in good condition and was probably changed not so long ago. I might try BOA 90LS or equivalent just to be sure, what do you think simon?.

[oilman]

I still can't see a reason why this is happening but lets try Boa 90LS so give me a call and we'll sort something out. 01209 215164

Cheers
Simon

[rockabilly]

you didn,t fill the gearbox through the gear lever did you?.

[car32]

mine does the same just when your parking or turning on full lock, i feel the rear wheels judder and you can hear them scrubbing,i thought this was normal for a lsd ive never had a prob with it

[Silver R33 GTR]

on my gtr when i first got it it was exactly like that. normal driving around fine but if i was trying to reverse into a parking spot it would judder and shake the whole car. after trying to reset reshim it 3 or 4 times i eventually slapped a new diff in and its been fine ever since.

im not sure if they are the same symptoms as yours but i just thought id try.

lets hope they're not and you dont need a new diff.

as for what someone else said about on full lock, when i pull out of a junction on full lock the inside rear wheel always scraps away and trys to spin.

robin

[Asim R32GTR]

I had the same problem on my car, changed the oil to Redline and added a some additive, and it works like a dream!

It is the wrong oil i think....

Try to turn the car with the clutch engaged... if the juddering stops... then it is the oil....

Asim...

[oilman]

It is not the wrong oil! Redline is also a 75w-90.

Cheers
Simon

[Asim R32GTR]

Originally Posted by oilman

It is not the wrong oil! Redline is also a 75w-90.

Cheers
Simon

Sorry.. my english isnt that good
It is the right oil type, but he needs to put in additive? oil... so that it makes the oil a littlebit more slippery, the problem is that the disks keep locking up during hard cornering... hense the jiddering...