Toyota T-100, 108,000 miles. Have done several drain/refill using conventional fluids, and want to know of any potential problems/benefits with switching to Mobil synthetic trans fluid.
The problem I would have is that drain and refill does not replace all the fluid. So for me to use I would have to be really sure about compatibility. Have a heart to heart with a dealer service rep. and the exact fluids you have in and plan to use. I personal would leave with the same girl I brought to the dance. I see no advantage unless you’re towing, plowing or never plan on changing it again before you sell
Unless the owner’s manual specifies synthetic fluid, or you are using the truck for some REALLY heavy-duty work, I see no advantage in switching to synthetic.
Why are you thinking about switching?
If normal transmission fluid has worked well until now, why switch?