How often do you or are you suppose to change the tranny and rear diff. fluids? Any good fluids to put back in? I was thinking Lucas. Thats what I have been using in the motor and fuel. I want good stuff, dont wanna half-***. Not worth it to me. My truck is a 03 4x4 dually. Is there anything else I should be checking or changing, other than the basics? This is my first diesel and my first 4x4. So any pointers are a great help.

 

I do mine every 15,000 miles.

I run Walmart Supertech Mercon 3 in the trans/T Case and 8ow90 in the diffs. I think I have Napa brand right now. I just buy it in 5 gallon buckets.