What type of oil is recommended for rear differential?

[gfield]

I have an E36 M3 (1997) with 102,000 miles. I can hear the rear differential humming/whining when coming off the power at low speed. What oil/lubricant is recommended to replace it with? The dealership says "it's sealed, we don't touch it".

[RAYADAM]

I have personally have used 75-90 Mobil one synthetic gear lube and Redline 75-90 synthetics as well..
I am sure a few guys here will chime in with there opinions...

the person you spoke to at the dealer obviuosly must not be familiar with the older generation maintanence schedules..If my memory serves me right,the MFR recommended service intervals for the differentials of that year was at the Insp II service (approx 60k miles).

your noise issue could be low fluid level (leaking?),degraded lubricant,or simply a worn out unit...

good luck

[taxwoman]

we use Redline on our cars at 40,000 miles as per Mike Miller

[rpob5t]

+1 on redline way tougher stuff than even mobil 1, use the same weight gear oil (75-95 IIRC) in my E30 track car and I had fluid boil issues with the mobil 1 (bumper was covered with gear oil spatters) where the redline never gave me a problem.

[davidmcintyre]

he dealership says "it's sealed, we don't touch it".

The person you spoke to at the dealership is a complete moron. If they were any kind of service manager or other manager, you should probably consider going to another dealership (and possibly telling us all what dealership we should avoid).

Geesh.

-dave

[victory1auto]

I too have had good luck with Redline 75W-90 synthetic gear lube.

Re dealership, are you saying that they did not even suggest that the fluid level be checked?

Vic

[jnscaldwell]

I'll throw in another positive on the Redline 75w90 as I have used it with excellent results. The Amsoil 75w90 is good too if you can get it.

[aikimo]

Greg,

Hello. Redline 75W90 is an excellent lubricant.. Will tell you that I was getting a lot of spitting from my diff when I used it in the race car.. I changed to Mobil 1 75W90, and no more spitting... Either one is good..

Best
Mo

[gfield]

The dealership in question was Wide World of Cars now part of the New Country family. The only thing that was said to me is that the rear differential is sealed and that they do not touch it on this model.

I would like to thank David Finch and let people know that he went out of his way to help me change it at his house. The fluid was filthy but at least there was still some fluid in there. We used Amsol 75-90 with a special allen wrench purchased from Ken at Bimmertools to make short fast work of it.

Thank you David!

[RAYADAM]

I have an E36 M3 (1997) with 102,000 miles. I can hear the rear differential humming/whining when coming off the power at low speed.

Well,did it correct(or minimize) this noise?

[gfield]

I cannot hear the noise anymore, but I have not had a chance to really bring the car up to speed yet.