Oil for differential?

[drummer]

What grade of oil do you use in your rear differential and do you change the rear differential oil with every oil change? (This is based on an average of 3K miles per oil change)

[Andy VH]

I have a 94 R1100RS, with 120,000+ miles on it. I use 80W90 Castrol Synthetic gear lube (same in the transmission). I change the rear drive fluid every other year, mostly. Certainly you can change it with every oil change if you want too, but there is no real reason to do that.

If you do a LOT of rain riding you may want to change it with every oil change. But again, its not necessary. I use synthetic oil in my RS, and I change my oil between 4,000 to 5,000 miles. Never had a problem.

[r1150gsadvrider]

check out benchwrenching in this months BMWON.

[drummer]

The BMW ON mag is what prompted the question. I usually perform one or more of my oil changes a year. While the dealer does the ones between, I am wondering if they do the differential as suggested. If not, I better get to it this weekend.
:brow

[PMonk]

after the vermont rally there was a lot of talk about why you should use conventional oil in final drives. Even some suggestions that the synthetics might be responsible for some final drive failures. I don't know about that. Anyway I had a final drive leak and the bottom of the drive was always black from the rubber boot back. I went back to conventional oil and the leak has stopped.
I use conventional engine oil, but synthetic in the transmission. No leaks and I feel like it shifts better.

[jingdog]

I didnt know the FD had a differential in it!:brow