Proving a clutch disc LSD is working ok?

[sdowney717]

This LSD differential is in an Isuzu 1996 Trooper. It uses clutch packs.
Jacking up tires, turn one wheel, other turns in same direction which is good.
Holding one wheel from spinning and turning other wheel takes about 10 pounds of force.
Driving with one wheel on grass, other on wet pavement in the rain, the tire on grass spins, but it does drive back onto the road.

Driving on a loose gravel parking lot, both rear tires spin the same amount when gassing it, would an open differential also do that?

When driving Trooper up on 4 metal portable car ramps to work on it, each wheel has a ramp, the right rear wheel spins and it has a hard time getting up, in 4wd it gets up these 4 ramps no problems.

So are the clutch plates worn and not giving enough torque to the non slipping wheel?

 

[bdcardinal]

Originally Posted by sdowney717
This LSD differential is in an Isuzu 1996 Trooper. It uses clutch packs.
Jacking up tires, turn one wheel, other turns in same direction which is good.
Holding one wheel from spinning and turning other wheel takes about 10 pounds of force.
Driving with one wheel on grass, other on wet pavement in the rain, the tire on grass spins, but it does drive back onto the road.

Driving on a loose gravel parking lot, both rear tires spin the same amount when gassing it, would an open differential also do that?

When driving Trooper up on 4 metal portable car ramps to work on it, each wheel has a ramp, the right rear wheel spins and it has a hard time getting up, in 4wd it gets up these 4 ramps no problems.

So are the clutch plates worn and not giving enough torque to the non slipping wheel?



An open diff would spin one wheel.

 

[sdowney717]

Originally Posted by bdcardinal
Originally Posted by sdowney717
This LSD differential is in an Isuzu 1996 Trooper. It uses clutch packs.
Jacking up tires, turn one wheel, other turns in same direction which is good.
Holding one wheel from spinning and turning other wheel takes about 10 pounds of force.
Driving with one wheel on grass, other on wet pavement in the rain, the tire on grass spins, but it does drive back onto the road.

Driving on a loose gravel parking lot, both rear tires spin the same amount when gassing it, would an open differential also do that?

When driving Trooper up on 4 metal portable car ramps to work on it, each wheel has a ramp, the right rear wheel spins and it has a hard time getting up, in 4wd it gets up these 4 ramps no problems.

So are the clutch plates worn and not giving enough torque to the non slipping wheel?



An open diff would spin one wheel.

I dont know, consider the gravel parking lot, if both wheels had equal traction I could imagine it doing either one tire spins other doesn't, or both tires spin the same.

 

[JLTD]

How many miles? From previous reading a LSD clutch pack lasts from 100k to 200k miles depending on how much it is used.

Throwing gravel from two wheels takes a lot less torque transfer than your ramp example. From your description I'd say it is still working but to a much lesser degree than when new.

Guess a rebuild depends on how badly/how much you use it.

 

[sdowney717]

Originally Posted by JLTD
How many miles? From previous reading a LSD clutch pack lasts from 100k to 200k miles depending on how much it is used.

Throwing gravel from two wheels takes a lot less torque transfer than your ramp example. From your description I'd say it is still working but to a much lesser degree than when new.

Guess a rebuild depends on how badly/how much you use it.

206,000 miles.
If you put the wrong fluid in it you can feel it isn't right when cornering under power.
Knowing i was going to replace the front diff fluid, I tried a mix of 50-50 gear oil with Lucas lsd gear oil. I noticed it was not feeling like it should, Drained it out put that in the front axle and put 2 qts Lucas LSD gear oil and it feels normal.
I do think it is somewhat tired. Thing is you can no longer get new clutches.
I was thinking shimming them tighter, or refacing the clutch discs, if I wanted to make it better, but I probably wont do anything.

 

[code5coupe]

Originally Posted by sdowney717

I was thinking shimming them tighter, or refacing the clutch discs, if I wanted to make it better, but I probably wont do anything.

If the clutch PLATES are worn, the only remedy is to replace them.
Shimming the springs, or refacing the discs will not only cost you more than repairing it correctly, they won't permanently correct the problem.
If you're going to do it, do it right.

 

[Asterix]

10ft-lb of breakaway is very little. An easy experiment is with oil and slip additive. Use an oil without additive already in it, like Redline's 75W90NS. Get some slip additive in a small bottle from Ford or Redline.

Change to the no-additive oil and see how bad it is, then add a little slip additive at a time until the diff quiets down to where you can stand it. Test while turning sharply, like in a parking lot at low speed. It will take a few low-speed figure-8s to get the oil all over everything. Keep in mind that it's easy to add slip, but to remove it you have to dump all the oil and start over. With too much grip it will drive badly and eat your tires.

In my experience, gear oils with the slip additive already included have way too much and kill the clutch action.

 

[buck91]

Sounds like its pretty shot. Maybe not gone but time for a rebuild if you value the LSD function. My 96 Mustang was in a similar situation at about 90k miles. I rebuilt the trac-lok with the carbon fiber clutch pack that used to be available. Worked well for a while but 50k miles later it likes to spin the inside tire on hard corners... through it lays two strips of rubber off the line!

I did a +1 clutch pack mod on my old Crown Vic back in the day. Worked REALLY well. Took a little bit of break in to smooth out due to the tighter setup, though.

Nothing compares to the Eaton Posi I put in the 9.75 in my F150, though. I have 2-3 times to recommended FM onto of running amsoil SVG. Its smooth most of the time but when it gets slick out, or if I come out of a corner hard that inside axle locks up every time and I get wheel hop. Does make for some fun Michigan lefts under moderate power... Even with my 33" tires.