Testing rear Lsd

[BarraSSRX]

I lined up with passenger side wheels on wet grass, driver side wheels on tarmac, in 2wd, started off with revs high and os rear on grass spun - watching it in mirror - Surf moved forward ok
So rear lsd diff seems to be working at least, its a '92 2.4 with 4 pinion lsd at rear - according to plate - haven't looked into it.
Was just wondering how to give it a good test to see if its working well or just working a little, maybe tow something heavy with same test applied?
Presume if it's working well it can make a big difference in 4x4
Looking forward to some snow soon

[slobodan]

If I'm correct, the LSD is a series of little clutches, It either works or it don't not 'works a little bit'.
I usually see if they are OK by driving in a tight circle on tarmac and see if there is and 'juddering' coming from the rear.
If you jack up the rear axle and spin a wheel, then the other rear wheel will spin the same way if it's got an LSD, as opposed to the opposite way if it hasn't.

I think.

[tweak'e]

they do actually "work a little bit".
a LSD is not on/off and should not cause juddering while turning tight, unless its been shimmed up real tight.
an LSD is a clutch pack, its slips like riding the clutch. it limits the slip but more power you put down the more it will slip.
so with one wheel on the grass you want to be gentle on the throttle.

being a clutch pack they do wear and also need regular oil changes. oil change can make a big difference.

[BUSHWHACKER]

Inside a LSD diff.....(TRD version)

[BarraSSRX]

Thanks for the replies, and a great illustration Bushwhacker
I was putting extra throttle to make get full wheel spin while checking if it drove forward at the same time as the spinning, to confirm if other wheel on tarmac got power, maybe I'm wrong but I think that indicates the lsd works at least, but maybe it would be better test to jack up one side at rear (don't know if it matters which side) and then see if it can drive off the jack

[Albannach]

but maybe it would be better test to jack up one side at rear (don't know if it matters which side) and then see if it can drive off the jack

Seriously?

[BarraSSRX]

Seriously?

Yes well it may be better than my previous test, I think if I place a bottle jack under the back axle and just raise one rear wheel an inch off the ground, then in 2wd at low revs ease out clutch and maybe even apply some light brake pressure, then the lsd if working ok should drive the Surf off the jack, if not the raised wheel would just spin taking all power like with an open diff

[slobodan]

Seriously?

I always look at the location first.

[BarraSSRX]

I've heard it maybe possible to restore lsd function by fully draining lsd diff oil then putting in half a litre of engine oil flush and driving for several hundred miles then empty and refill with lsd diff oil, would seem like a too easy solution over shimming / fitting clutch plates / tightening up

Anybody here ever do anything like this with engine flush on a Surf lsd and notice any benefit?

[tweak'e]

if it needs shimming then no amount of cleaning will make the lsd work.
i would not run engine flush in a diff unless you want to replace bearings fairly quickly.
most of the time lsd not working because the friction additives have broken down and its effectively running on normal diff oil. very rarely that you have cooked the oil and contaminated the clutch pack.

for testing don't drive off the jack you dumb buggers!

just jack one side up, block it (or put stands underneath), then jack the other side up. tune the wheel and see which way the other wheel turns. (gearbox in neutral).

[BarraSSRX]

for testing don't drive off the jack you dumb buggers!

just jack one side up, block it (or put stands underneath), then jack the other side up. tune the wheel and see which way the other wheel turns. (gearbox in neutral).

That's a pussy way of doing it no fun at all my way rocks the jacks off

[muddle]

You're a cock.

[tweak'e]

does that make a new meaning to the phrase "jacking off" ?

[slobodan]

That's a pussy way of doing it no fun at all my way rocks the jacks off

I concur with that.

[TonyN]

I've heard it maybe possible to restore lsd function by fully draining lsd diff oil then putting in half a litre of engine oil flush and driving for several hundred miles then empty and refill with lsd diff oil, would seem like a too easy solution over shimming / fitting clutch plates / tightening up

This isn't a good idea unless your oil is really manky (in which case you're buggering it up anyway), and I wouldn't drive it for very long, a few miles at most, function on the LSD isn't changed by non-LSD oil, in fact I'm given to understand it works better, but life span is considerably reduced without the LSD additive.

You can't replace worn friction material by changing the oil.

I'm not sure you'd be able drive a clutch type LSD diff truck off a jack, even if it's really new and tight, even if you're dumb enough to try, you need a locker for that.