Re: RE: Is my LSD broke?

From: David Gersic (info@zaccaria-pinball.com)
Date: Mon Mar 30 2009 - 17:07:38 EDT


On Monday 30 March 2009 01:55 pm, Bernd D. Ratsch wrote:
> You can, however, get the diff to lock by lightly applying the brakes while
> moving.

I'll keep that in mind. I don't know if I'll get another chance to test it on
road. It's in the 50s now, and the snow is almost gone.

> One thing though...if the clips in the clutch pack break (which happens
> quite often on the 9.25" diffs), you'll also get the same symptoms like you
> are describing.

Thanks. I should have mentioned that I have the 8.25" diff. The FSM drawings
of the Trac Loc for the 8.25" and 9.25" seem to be the same. There's 110K
miles on it, of which I've only put on about the last 15K, so if this is
common, I'm willing to be that it's what I probably have. The clips are what
the FSM has labled as the "retainers"?

Is the torque wrench test [1] in the FSM sufficient to prove that the LSD is
good or bad? Or is disassembly of the rear end to inspect the clutch packs
required? If I have to take it apart, I might as well get the parts and
replace the clutch packs. If the torque wrench test will tell me *if* I have
to rebuild it, that's easy to do.

[1] Trac Loc diagnosis and testing:

The differential can be tested without removing the differential case by
measuring rotating torque. Make sure brakes are not dragging during this
measurement.

(1) Place blocks in front and rear of both front wheels.
(2) Raise one rear wheel until is is completely off the ground.
(3) Engine off, transmission in neutral, and parking brake off.
(4) Remove wheel and bolt Special Tool 6790 to the studs.
(5) Use torque wrench on Special Tool to rotate wheel and read rotating
torque.
(6) If rotating torque is less than 22 N-m (30 ft. lbs.) or more than 271 N-m
(200 ft. lbs.) on either wheel the unit should be serviced.

The Special Tool 6790 looks to be just a plate with some holes in it to fit
three of the wheel studs and providing a center attachment point for a torque
wrench. Lacking Special Tool 6790 here right now, I can probably make one out
of some plate or bar stock.



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