Does anyone have any advice about the interval for changing the Tranny and
Differential fluids in my '98 1500 5.7L Vortec. I bought the vehicle used
with about 50K on it and it now has about 72K. I have been changing oil
using Valvoline Synthetic at approx 3K intervals.
At about 57K we purchased a travel trailer that is about 4500 lbs loaded.
At 59 or 62K (I don't remember exactly) I had all of the fluids flushed
and replaced. I used synthetics for all of the fluids where available
When I was in for the 71K oil change, the Service Tech said that the
Transmition fluid was "duller" in appearance than it should be and
suggested changing it. I have towed the trailer about 3500 miles and was
thinking that this seemed like a shorter interval than I though it
would/should be especially using the synthetics.
Any suggestions on estimated mileage? What would be the best way to test?
I don't mind paying to change the fluids frequently if that is required
under these conditions but then I also would question whether the
synthetic fluids are to any advantage?