T series diff lsd - stutter / shudder when turning

[djscheppy]

Hello gents

Did a quick search and couldn't see this question answered


Car : Adm AE86 (small diff conversion)
Motor : 4agte
Use: Street
Problem : rear wheels stuttering / locking while cornering
Occurs: just completed the swap last weekend from the s series. on the straight there's a slight low whine while driving but not too big a deal. Did the conversion, ran the car on the hoist to get the new oil up to temp. Drained the centre and refilled with new clean fluid.
Was quite a bit of metal in the wash out oil (and turned a milky yellow colour) but nothing too concerning.
Reversed out of the shop fine, went to turn out into he street and the wheels started stuttering / locking when turning. Got out checked the connections, axel, wheel nuts etc all seemed fine. Drove it straight and no locking/stuttering.

Stutters when turning in either forward or reverse. No stuttering when straight forward / reverse.

Some googling says it might be clutch worn or sticking ?

I haven't had lsd before so don't know what I should be looking at.

Anyone know what this might be and any part numbers I need to chase up?

Cheers




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[johl]

just sounds like it has a welded centre or a very tight lsd. either way nothing to be concerned about. my old cusco 2way lsd would lock the wheels when i was parking my car or turning at very slow speed. no where near as much as a locked centre but still would do it

[Hen may possibly be a nut]

Yep, sounds like a tight LSD. Generally good, though mildly annoying at times.

While driving it for a while might help, you can also run it in, which really helped with one of my LSDs. It involves doing tight figure 8s with the clutch in while you're turning. For 10-20 minutes or so. Google should turn up a better description from a Cusco?? manual.

Hen

[djscheppy]

Hm pretty sure it's not a welded centre. But this happens all the time. Pretty annoying when parking lol !

That's really helpful. Will try the figure 8s tonight.

Any visual inspection I can do to be sure ? Think I might open the centre up this weekend.


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[djscheppy]

Hm, was doing the figure 8s in the slick after it rained tonight. for about for 10-15 mins and no luck. Still skidding like a mofo. Should I give it another shot?


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[Hen may possibly be a nut]

When doing the figure 8s you shouldn't be drifting. Drive straight, clutch in, hard left, straighten up, clutch out, accelerate, clutch in, hard right, straighten out, clutch out, accelerate. That is one figure 8, do them as tight as you can and for what feels like an eternity.

Your diff shouldn't shudder and grab while you are doing this as you are putting no power through it while turning, but it rubs the clutch plates against each other. It hops and carries on then you could well have a locker, or an unhappy diff.

[44GTE]

Hi

Go to HOLDEN spare parts and ask for some LSD treatment, comes in a small bottle from memory 50cc. Remove fill plug on level ground , may need to drain or suck a small amount of oil out and then squirt all of it into diff. Then reseal up and carry out tight figure 8's as previously mentioned. This will allow the penetrating oil to get in between the friction plates and should help.

Cheers

[Javal]

Hi

Go to HOLDEN spare parts and ask for some LSD treatment, comes in a small bottle from memory 50cc. Remove fill plug on level ground , may need to drain or suck a small amount of oil out and then squirt all of it into diff. Then reseal up and carry out tight figure 8's as previously mentioned. This will allow the penetrating oil to get in between the friction plates and should help.

Cheers

Was going to post this, but couldn't remember whether it was to suit cone or clutch type LSD. You can still get the friction modifier and it's fairly expensive for what it is but does work fairly well. I remember hearing a while back that the formula for the friction modifier had been incorporated into castrol SAFXA oil, which is the recommend lubricant for the VT-VZ LSDs. It does kind of sound like an extremely aggressive LSD or a welded different though. If you've got the time and can be bothered pulling the center out to have a squiz, I'd recommend it. If you do find its got a LS center, you could try using the oil recommended by the manufacturer.

[44GTE]

Its a TRD LSD centre

[LittleRedSpirit]

Penrite also make lsd additive and the diff shop gave it to me along with Penrite LSD oil to put in with a lexus torsen type 2 diff. Clutch lsds definitely need it for the reason described above, I was surprised they gave it to me for the torsen as it works differently, but it must be required wherever slip and grip are in different circumstances.

You might also consider having it adjusted. Some people like them to work basically like a locker and tighten them right up. Having had two different trd 2 way lsds I can say they usually don't grab when turning with zero throttle input. I used to detect it start to shudder and grab a touch as I feed the power out of turns but you just get to a point to where it locks up and that transition feels smooth so the shudder is often barely detectable, or only noticed when you maintain that in between throttle input.

Straight running wont lube the plates, you need to do the figure 8s in alternating directions while slipping as mentioned to lube them right. If you cant get it to slip, you cant get it to lube. It almost sounds like you didn't use LSD oil. Have you double checked you didn't use Just Manual gear oil by mistake?