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.:cheers:

http://www.ls1.com.au/forum/showthread.php?22665-Clunky-Diffs/page2&highlight=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


Sent from my iPhone using Tapatalk 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?

[Usdrothek]

Wasn't there a thread about this diff problem? The diff crush sleeve being loose causes that clunk.

[Nutter]

Without seeing or driving the car its hard to say but it sounds like diff chatter, your old diff may not have done it with penrite because the lsd cones or friction plates depending on what Centre it runs weren't pre loaded as much as the fresh install. What often happens when people set up lsd centre's is they shim them to get more pre load on the cones or plates so there's less chance of it kicking out to single spinner, the downsides include premature lsd cone/plate wear and chatter even with the correct additive and the symptoms are usually worse with tighter turning and low speed.

If the pre load on the crush us too little the diff will clunk and possibly whine due to incorrect mesh but usually only when you either get on or off the throttle, more prominent in manuals. It's unlikely to be related to the donuts, the most common symptom with them is vibration under load, if they were chewed out enough to clunk the car would rattle your teeth out.

Sent from my HTC One XL using Tapatalk 2

[Craig93]

Hey guys it was the diff.
clunking got pretty extreme when going around corners and stuff.
took it down to get it looked at and just as i pulled in it started locking up and stuff.

[Wonky]

Was it a new or used diff centre, or did you have a diff place swap the gears for you in which case it should be under warranty?

[Craig93]

Was it a new or used diff centre, or did you have a diff place swap the gears for you in which case it should be under warranty?

hey wonky. It was a diff centre i purchased over the internet. was told it only had 30,000ks ;/
it looked super clean and stuff but yea idk it was no good.
gonna send it away and get it looked at then see what to do.
back to the trusty 3.45 for now but.

[calais190]

Lucky you held on to the 3.45 Craig! Seems like everything's happened the way it has for a reason! Hope you get it sorted cheaply mate...

[Wonky]

hey wonky. It was a diff centre i purchased over the internet. was told it only had 30,000ks ;/
it looked super clean and stuff but yea idk it was no good.
gonna send it away and get it looked at then see what to do.
back to the trusty 3.45 for now but.

Ouch!! That's gotta hurt, though as I said above, I know of a few people who've had problems with 3.7s in their VEs, even brand new bought from a dealer. Doesn't make sense because non-HSV and HSV VEs are essentially the same beast.

[Craig93]

Lucky you held on to the 3.45 Craig! Seems like everything's happened the way it has for a reason! Hope you get it sorted cheaply mate...
Yea tell me about it mate haha thank god woulda been rooted otherwise haha.

[Craig93]

Ouch!! That's gotta hurt, though as I said above, I know of a few people who've had problems with 3.7s in their VEs, even brand new bought from a dealer. Doesn't make sense because non-HSV and HSV VEs are essentially the same beast.

Yea thats weird you would think there the same same inside so its abit strange. Ive never had a problem or heard a sound out of the stock one.