You should change the diff oil. Syn is originally in the back and dino in the front. Go to syn in both. You should change the spin on tranny filter either every oil change or every other change. I do mine every 10k miles.
These trucks are ment to pull trailers thousands of miles before needing any kind of maintenance. I change my trans fluid *filter and gastket too*, diff fluid, t-case fluid and some other stuff every fall. But I tow with mine 2 days a week and put about 30k on per year, and by changing it once a year certainly cant hurt. But after 200miles? Comon, thats way too exessive :blahblah:
I agree. I live in my 5er, and pull it everywhere. Once a year, or if I am pulling long grades for a LONG time with a BIG headwind, I might change it to be safe. The manual states the front and rear diffs are to be changed every 100,000.
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