I just bought a 1993 Dodge Ram W150 that hadn’t been used much in the past year. It runs good for the most part but doesn’t seem to want to shift between 35 and 55 mph. If I get on it and get it to 55 then it shifts into overdrive and is fine. Any advice on what to do to fix the problem.
If the fluid level is good (Check hot with gear selector in “N”, on level surface) then I would pour in a can of Berrymans B-12 Chemtool. These transmissions are known for leaking front clutches, the B-12 will soften the piston seals and temporarily stop the internal leaking. If the trans behaves right after the B-12 treatment we then know what needs to be done to permanently fix the issue. Rebuild.
This is what you want to buy, I get it at Wal Mart, Pep Boys, and Advance auto parts.