72,500 miles later and 2nd drain and refill of Differential
 

The first time at 133,000 miles and it stunk beyond belief. If you have ever done the job you will know how bad it can be.

Both times I used a quart of Red Line MT-90 75W90 Gear Oil with a M1 top up for the last bit.

This time out 72,500 miles later and it was dark in color but still smelled fresh.

Doesn't cost much for lots of protection and peace of mind.

Same old tip "REMOVE THE FILL PLUG BEFORE THE DRAIN PLUG!" You know why!

About to do it for first time on my 98 at 79k miles....plugs too rusted to insert hex bit into, so I've been spraying with penetrating oil and will try again soon.

I had the same thing happen on a BMW M3.
I "polished" the hex just slightly on a grander, tapped it in with a hammer and all was well.