Diff swap now car being strange??

[Craig93]

Hey guys, i had my diff centre swapped out yesterday for a 3.7 in my VE SS commodore.
Driving it today i have noticed that it has a thud sound every once in a while when i take off.
Any ideas what it could be?
Thanks

[steve_t]

Could be diff lash but also check tailshaft, driveshafts and their donuts, yokes etc

[FrangaFry]

Do you feel the clunk if the steering wheel is slightly turned (at slowish speeds) - I had a similar issue and it was caused by the LSD being too tight after the re build, doesn't cause any problems (so I am led to believe), and was told that it should bed in, but the sound was disgusting (sounded like a little dwarf with a BIG hammer under my car when turning slowly) so had the diff replaced/rebuilt again and no more banging sounds.........

[whitels1ss]

Very common problem if you have the wrong diff oil or needing the correct Holden LSD additive.
The Holden LSD's must have the correct lubricant otherwise they will do exactly this.
Try using the search function and you should find a few threads on here with more information on the problems.
I will see if Ican find you a liknk to a thread for more reading and post it for you in a while.

[whitels1ss]

There are a couple of posts on this thread about the clunks on a new diff and requiring the additive but it is not
the exact thread I was thinking about. Anyway it might give you something to think about and put your mind to
rest as changing diff oil or putting in the correct additive should not break the bank.

http://www.ls1.com.au/forum/showthre...ight=lubricant

Post 19 and Post 24 are good even if you don't read he whole thing.

[VZ_V8]

The friction modifier you are talking about is Sturaco 7098 however that is usually only put in when the clutch plates are biting too hard when cornering if your normal diff oils are used like Castrol SAF-XA etc they have the modifier already in them. The thump on accel in a straight line when both wheels are moving at the same velocity is usually caused by backlash, mine started doing it more when I had the 3.9s put in and even when I had the diff rebuilt again when I had the tru-track fitted, the noise stayed exactly the same.

[Craig93]

Thanks for all the replies guys.
Ill drive it tomoro and give it a good listen to see when the sounds are happening.
The oil i used is penrite and i used it in my old diff with no sounds or anything so i would think its ok.
thanks

[Craig93]

Hmmm diff has started making more clunk sounds than before especially when going slow and turning. Almost sounds like someones in the boot trying to kick there way out lol. Doesnt sound good at all.
Any clues what is up?

[whitels1ss]

Hmmm diff has started making more clunk sounds than before especially when going slow and turning. Almost sounds like someones in the boot trying to kick there way out lol. Doesnt sound good at all.
Any clues what is up?

Buddy, as I said before it will be the diff oil needs changing or the special additive.

[Wonky]

I do know a number of guys on here who went to 3.7 in their non HSVs had them fail relatively early on, even brand new ones eg. Dean (EXCESSV) from Perth.

[VYSHSV8]

I do know a number of guys on here who went to 3.7 in their non HSVs had them fail relatively early on, even brand new ones eg. Dean (EXCESSV) from Perth.

He will blame me for that lol


iPhone in the middle of Farkin no-where

[Craig93]

Buddy, as I said before it will be the diff oil needs changing or the special additive.

Yea but the oil in it was in the old diff aswell with no problem.
And it has the additive aswell.

A few people have said it could be the diff coupling bolts maybe snapped?
It doesn't make the sound when in neutral going around corners?

[FrangaFry]

Bud, I rek'n it's your LSD, sounds exactly like the problem I had. Slow turning, major banging... I sh1t myself when I had it first time. You can try the Kaaz figure 8 bed in process, I was told this might help. Or take it back to you re builder and explain the prob, he should fix under warranty.

[Craig93]

Yea gonna put it on the hoist this arv see if anything can be seen or noticed if not I'll have see what can be done

[aratic]

Was the centre a used or new part?