grouchy LSD (G series)

[urantia]

I have this 4.3:1 LSD i buaght a few years ago and it's been trouble since day 1, i had put some castrol LSX90 in it when i first got it, and it was atrocious, the clutches would resist slipping on slow speed corners, surprised the diff isn't busted from the amount of noise it was generating.

The next oil i tried was a really thick penright LSD oil (blue in color) wich was recomended from negative boost, which pretty well fixed my problems well i thought it did, until that is the diff warmed up then it was back to it's old self of protesting on slow corners, and generally making my car feel rouph overall when driving.

The severity is much less but still not acceptable. I was going to get a torsen but after having a lengthy discussion with Andrew Vibert who talked me out of getting the torsen recomended i try this GM LSD additive a try first.

I think this is the stuff andrew was talking about:
https://ssl.shoalhaven.net.au/usgmse...oducts_id=3099

Has anyone had simular issues with there LSD and had any luck with an additive like this or a particular cure? I beleive the diff is still good, the oil is still clean, and there are no metal particles either. What do others use in there G series LSD's?

[kingmick]

Did you buy it second hand? and was it rebuilt that you know off?
You might find it isnt setup well or old and in need of redoing. Might have had a hard life before you got it.

[urantia]

Yeah it was second hand, bloke i buaght it from said it was rebuilt. He sent it down with fresh LSD oil, but it all leaked out of the breather into the couriers van, gee he was in a slopy mood when he delivered it LOL.

So the additive is probably a waste of money?
Hmm LSD's are a black art to me, setting the preload and all those things, sounds like an expensive job of getting a diff specialist to take a look at.

thanx KM

[ddeane]

Urantia

The problem is not with the LSD but in the way it has been set up. For competition use you dial in more preload that means it resists 'Differential action' under normal driving conditions. Ie the inside wheel want to turn the same as the outside wheel even at low speeds. I had a T series that exibited all of the characteristic that yours is.

Solution - Take out the centre and take it to a Diff specialist and ask him to adjust the preload on the clutches to suit your needs. Cosy me less than $80.


Craig

[urantia]

Craig, sounds along the lines of what Andrew Vibert was saying, altho he reckoned this GM Additive was worthy to try.

I suppose the thick LSD oil worked well until it got hot and thinned out allowing the clutches to get more friction.

$80 is the going rate for adjusting the preload? yeah thats pretty good. I don;'t know of any diff places in my area, there would be some but i probably wouldn't trust them to get it right like most services around here. Anybody done this themselves?

[kingmick]

Yes its needs doining again by the sound of it to check the meshing of the gears and preload! it shouldnt be to expensive if its been done before resently.

[ekoston69]

hey this is interesting, i never realised you could adjust the preload.. if you tighten the preload i assume the clutches will wear faster?

[kingmick]

there more slip the more wear, like riding a clutch!

[ekoston69]

ah that makes sense lol, so the less slip, the noisier and more uncomfortable? But the tighter?

[urantia]

interesting, seems there is more to the LSD then meets the eye.

I also have some pretty major play in the diff, if i'm not smooth on the clutch i get a nice jerky clunk on take off, also the same when letting off the throttle while driving. Checked the tailshaft out and the diff seems to be where the play is. This would all be in the crown wheel and pinion mesh contact area? Just another reason to take out my LSD and and get it checked/adjusted.