Overly active LSD - anyone experienced this?

[amacatan]

This is related to my thread -> http://www.landcruiserclub.net/foru...-grinding-noise-when-parking-Prado-97-3400-V6

The problem was traced to be the rear differential all along. The problem does not manifest after a cold start. After driving it for 15 mins, the rear differential sticks/locks and almost acts as one axle. We have dismantled the rear differential and we did not see any problems.

My mechanic suggests that we remove the spring that controls how much torque is needed before the LSD kicks in to make it behave as if an open-type differential (I do not need an LSD anyway). Anyone heard of this or done this before?

 

[wobbly]

How many miles has your truck done?

The lsd has an expected lifespan of 50,000 miles (80,000km).

To check it is opearting correctly:

From cold, jack up the rear, handbrake off, spin one rear wheel (you may have to put the truck into neutral). Remember to chock the front wheels, and dont start the engine!

The other wheel should turn in the same direction if the lsd is working correctly.

If the wheel rotates in the opposite direction, lsd is faulty.

Then run the truck for a couple of miles to get the diff oil warm, then repeat again the wheel rotation.

I suspect that your truck has had the rear diff oil replaced, and they have not used the correct oil when refilling it, it must have diff oil with lsd additive, otherwise the diff wont lubricate properly.

When was the diff oil last changed?

It sounds like they have used automatic transmission oil in the diffs.

Pete

 

[amacatan]

The diff oil has just been changed in hope to alleviate the problem. I used castrol axle limited slip 90. From cold, turning one wheel causes the other wheel to turn the same direction. After driving a few, same direction still.

I feel that the LSD "sticks" too much when it gets hot which makes it shudder during turns at slow speed.

 

[wobbly]

So the diffs are working, which is good.

I reckon the rear prop needs to come off, so isolating the rear diff, then run it around a car park and see if the problem is still there.

Bit early for bodging springs!

Pete

 

[mike hatton]

Running an lsd with standard oil causes it to stick and lock, usually happens after driving in a long straight line (motorways etc.). If it's had standard oil in the past it may have damaged the plates and put burres on them. I'd fill the diff with diesel then drive it in a tight circle each way, should clean the plates off. Then drain it and put lsd oil back in, you can add extra friction modifier too, the more you put in the more it will slip.

If you only ever drive in straight lines it may still catch on the occasion you turn a corner.

 

[amacatan]

So the diffs are working, which is good.

I reckon the rear prop needs to come off, so isolating the rear diff, then run it around a car park and see if the problem is still there.

Bit early for bodging springs!

Pete

Yes. We have removed the rear prop and the problem is still there.

What do you mean by bodging springs?

 

[amacatan]

Running an lsd with standard oil causes it to stick and lock, usually happens after driving in a long straight line (motorways etc.). If it's had standard oil in the past it may have damaged the plates and put burres on them. I'd fill the diff with diesel then drive it in a tight circle each way, should clean the plates off. Then drain it and put lsd oil back in, you can add extra friction modifier too, the more you put in the more it will slip.

If you only ever drive in straight lines it may still catch on the occasion you turn a corner.

Thanks for the reply. I'll try adding a bottle of friction modifier. I hope this works

 

[amacatan]

Thanks for the reply. I'll try adding a bottle of friction modifier. I hope this works

UPDATE:

I have put in a fresh batch of Castrol Axle Limited Slip 90 Oil plus 2 bottles of Redline Friction Modifier Additive. Problem still persists.

What's next? I am now inclined to follow my mechanic's suggestion of totally removing the spring in the LSD to alleviate torque. But before I do, I want to know anyone's insight on the implications it might produce.

I do not mind having it behave like an open-type differential. I just want a working car!

Anyone?

 

[silvercruiser]

It does sound like there is a fault with the LSD do taking it out to have a look at whats happening can't hurt. once its out you may see something you can fix or as a last resort try what your mechanic friend has told you.

 

[silvercruiser]

Bodge/ing = Not really fixing it properly.

 

[Graham]

Whip the spring out, see how it behaves.

If your not planning any serious off roading, then what's the problem?

It will still be 4 wheel drive any way.

For me, I would have no hesitation in reverting it more towards an open diff.

Gra

 

[wobbly]

If you remove the spring and the problem goes away then you have clearly identified the lsd as the fault, so a good idea at this stage.

I suspect that the wrong oil has been used in it, as Mike says, this damages the faces.

At that mileage it shouldnt be the original lsd, but if it is, its led a very long life and is due for retirement!

If you can live with no lsd this is probably the simplest option, certainly a new lsd will be $$$$.

Let us know how you get on.

Pete