fralla

I think my diff has gone bad on the E55, when i let of the throttle i get a whining noise from the rear.
125K miles on it
Does the -98 E55 diff fit the 2001?

Differet numbers on them.
A2103503162 VS A2103503514

Agent-A01

Try swapping the fluid.

My 211 E500 i did the diff fluid with mobil stuff from autozone and it caused a whine.

Eventually swapped out to the OEM spec stuff and it fixed the noise.

fralla

Ok, thats a good start. What viscosity dit you put in it?

Agent-A01

Previously I used mobil 75w-90.

My fluid came out black but shortly after I started getting a whine at low speeds.

Eventually replaced with 75-85 fuchs sintopoid fe and it has been good since.
I also used it on my CL55 with no issues.

fralla

Ok, i will try that. Thanks alot