Had my oil changed today. I'd usually do it myself, but we're leaving tomorrow for our wedding and I just didn't get the time to do it at home. Anyway, the Tahoe has 29,000 miles, the fluid from the front differential was a dark grey/silver color, and the rear was more black, but looked fairly dirty. I was told this wasn't normal. What could be the cause for this? I've only had the truck in 4x4 about 5 times, otherwise its always in 2x4. Anyhelp?

 

The front and rear axles use different types off gear libricant.
The dark color of the lube in the rear is normal.
The silvery colored front fluid is a little worrisom depending on the amount of metal particles in the fluid, I would have it drained and flushed again in the next few months just to be sure that everything is OK.

 

Ok, thanks. I may just take it in to the dealer and let them have a look.