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[chrisgixer]

This dif works very very well. Still drives if one of the rears lets go, usually on broken surfaces or gravel, pulling away out of remote country roads etc. Can hear the slip from the rear if pressing on on Tarmac , it gives a cherp cherp cherp from the rears at wot in slow tight corners.

The judder from the rear is still very much evident too, so its defo working.

But there's been a change. The judder is not as uniform as it was. Its more random and less evenly spaced. Pull away with some lock on and the dif has to slip. It just does. But now its a bit harsher than first fitted, and the slip/judder frequency is more higher. Approaching harsh at times.

When fist fitted... Boom boom boom boom, relate to road speed.
Now... Boom boom bbbbbooom   ....   Bbbbbboom boom boom. Etc. best I can describe it anyway.


Polys exaggerate the effect btw, but the change has occurred a good while since footing rear donuts.

Is it worth an oil change? Probably only done 5-7k since install.

After thought, it changes with use. As it gets hotter maybe? Hotter=more judder.


As a note, her ls300 has an LSD fitted, the sensation is much less noticeable, but utterly uniform. Nearer, bbbbbbbbbbbbbbbbb. Much higher frequency. No reason it should be the same I suppose.


I wonder if the slip additive ratio is correct. (I didn't fit it)

[chrisgixer]

I should add, the grip from the rears is enough that the rear rarely lets go. So its debatable if I need The dif at all. It never steps out as such, you have to really take the pesh and flick it out to get the rear to break away. 265 wide rears. Sc3.

[05omegav6]

How are the rear tyres wearing Is the width of them straining the diff in someway, worsening as they wear

[chrisgixer]

Wearing very well. I want to replace them as the rear started to tram line slightly a few months ago. But they are hanging in there, 2mill off the wear bars.

I keep thinking, must replace those tyres this month, them check the wear, nope, I'll get another month or two out if those. Good job too, as 265 40 18 ain't cheap.

The judder is completely unrelated to performance, in that just pulling out if my road sets the judder off, due to the turn radius. There's no wheel spin involved there so I can't see tyre grip drop off of this minor level being a factor. It will judder while parking for instance. Although it depends how warm the dif is as to how much.

[05omegav6]

Have you disturbed the input flange wonder if the preload is off, could be affected by heat...

[Dazzler]

Sure it's not prop shaft slap?

[Kevin Wood]

Sounds like the LSD itself if it's relative motion between the two rear wheels that cause it to judder. Guessing the input pinion preload wouldn't affect that. Maybe it's set up a tad tight?

Do you know what oil is in it? IIRC, 2Woody advised to avoid multigrade oils?

Might be worth dropping the oil to see if it's contaminated with anything, then fill with some BOA90LS?

[Kevin Wood]

Sure it's not prop shaft slap?

A bit of movement in the prop shaft could well amplify any judder from the diff. Having experienced it, it's certainly originating from the diff as it's powering out of corners that sets it off.

[zirk]

All the ones I've driven do give a one time clump or slight thump when pulling from a tight corner, is the noise your describing with the TC on or off, they can sometimes go into confused mode (slight oscillation) with the TC on, ie LSD tries to kick in and the TC having non of it.

Did come across an Estate once that was really bad on judder especially with TC on, felt like the back axle was trying to part company with rest of the Car, turned out to be a broken rear spring!

[chrisgixer]

Tc is very rarely activated. I never touch it tbh.

[chrisgixer]

Tc is very rarely de-activated. I never touch it tbh.

Sorry that should read as above. Tc is always on.

[2woody]

its probably down to ambient temperature. The instantaneous grip between tyre and road at low speed will be much higher at this time of year.