I've got a 3.07 diff from an '84tdt for sale in parts section.

Chet,
I've been told I should try a heavier weight diff fluid. Truck specs- 85-140w. That's what I'll try first before I pull the diff.
BioBens,
What would the 3.07 diff do to initial accelleration if the car came with a 2.88 diff? Also, do you have the speedo to go with the diff?
Mike

First thing I would do is drain the fluid and fill it with new Fluid. You can try some good synthetic fluid like redline or royal purple. Thicker fluid might help, but more than that new fluid will probably do the trick. I bet the fluid is low too.

benz diffs are known to be kindof whiny compared to others.

and it is true that a wagon will have more noise from one than a sedan for sure. no bulkhead to separate the noise from the passeger compartment.

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.