I’ve noticed that when I’m driving between 40-55mph the trans shifts between 3-4 constantly. It’s not hard or anything, in fact it’s very subtle, but it’s there. Also if I go above 65mph it throws a code 1870 for “transmission component slipping”. But it doesn’t slip. It shifts very hard from 1-2 though. I can get it to go away by clearing the code and it doesn’t come back as long as I keep it under 65mph. Bad solenoid maybe? Any suggestions?

 

Low on fluid? When mine was leaking really bad, the torque converter wouldn't stay locked up. Kept locking and unlocking at steady cruising speed.

 

It’s got plenty of fluid. I check it every so often. But the torque converter locking and unlocking makes sense. Would that be a new torque converter or a sensor?

 

Good question. My '95 is doing the same thing except no code. Full of fluid and does well otherwise. Going to try a filter and fluid chnage here next week, when I can find some time.

 

This has been the best at addressing the symptoms you describe. Other option is valve body replacement. The bores that the valves work in wear over time and leak.