97 f150 4.2 125,000Km, auto trans 2wd, problem started out after run/s on freeways coming to a stop at light, engine starts to stumble like the TC is locking up. Within a couple of months it is now very slow to go from D to R and slipping unless you feather the throttle. Have changed te fluid and filter and found no debree in the pan. Has shown now fault codes when checked.
How can you determine if trans or T.C.