I'm changing my diff fluid right now for the first time at 7,500 miles, and I'm wondering whether or not the oil keeps getting as dirty as it is now, which would mean I should plan to continue on with the same schedule. Or does it stay clean after the first change?

Please let me know about your second differential fluid change:

*Elapsed miles since first change,
*Brand/Type of oil being removed,
*How dirty it was,
*How "glumpy" it was.

Thanks!

 

I do believe that the dirty oil was just the milky gray color of the moly additive. It looks bad but actually it was doing just fine and had things in it that you don't have now.

 

I changed for the first time at 15K. It looked horrible; nearly black, goopy and gloppy. Put in Mobil 1 for a week (~100 miles) as a "flushing" oil, and it too came out dark grey (was a honey color when new), but thankfully still smooth. Then put in Redline Shockproof, which has been in since (7500 miles).

 

My first change was at 8500 KM (5300 miles @8 months), went to Mobil 1.
The second change was at 26,000 KM (16,000 miles @ 2 years), also Mobil 1.

The first change was really unnecessary as the original fluid was very clean and only a light "fur" covering the magnet.
The 2nd change may have also been unnecessary but that's when I did the gear swap. The fluid was a bit darker than the first time and again, only a fight "fur" on the magnet.
I'll be changing the fluid again next spring once my new gears are well broken in.
The book says to do it every year or 15,000 miles. I think I'll adhere to that schedule myself.

Destiny, are you (or have you) considering a slight overfill like for the tranny? I might at the next change- depends on what the fluid looks like.

 

No overfill for the diff...