davelinde

Can anyone enlighten me about my front differential?
Why should I change the oil in it on the same schedule as the rear? I think I know it's always turning, but it's rarely under load and rarely under extreme (towing) load. All told I'd guess I have more miles in reverse than in 4wd.

I did an early change on the rear because I had a lot of towing miles on it. I was going to let the front go all the way to the longest maintenance interval. Though I'm wondering about that.

Jim O

I did both diffs the first time @ 15000 miles or24000kms. and now I do the front every second time. I think you could get away with not using synthetic in the front diff. but I am not going to try it.
I had the oil anylised from both diffs with 49500Kms (30700miles) front diff and 15600Miles (25100kms.) on the rear diff and the readings were all lower on the front diff exept silicon and ( it was lower than the first sample when I changed the oil). I think the high silicon readings are either an additive in the original oil or assembly line dirt. When I changed the oil I switched to Mobil 75/90 synthetic I have changed the rear diff oil 4 times now and the front diff 2 times and the readings are getting better but the rear diff still has higher readings than I would consider normal.(Iron Chrome & copper).
Jim O

Jeff in TD

I doubt it is really necessary to change the front every 15K, though I suppose it could be argued that the front never gets warm enough to bake moisture/condensation out...

I figure I will keep changing mine on schedule, even if it is just to keep the warranty well lubricated.

Since I have to get the tools and drain pan out for the rear anyway, it really isn't much extra work.

bulabula

I do it because my truck is still under warranty, and the book makes no distinction between the front and rear diffs in the maintenance sked.