Vehicle is a 2004 Ford Ranger V-6 4x4 5 speed standard transmission extended cab pickup.
Two years ago it was shifting extremely hard and was diagnosed with a bad slave cylinder. I had it replaced and as it was apart, had a new clutch put in also. Several months later, it still wasn't right and they replaced the power pac and the clutch under a warranty. Still was never really right. Ten months or so later, the transmission locked up in 4th gear and had to replace with a rebuilt one. Different shop this time as I was away from home. Week or so later the slave cylinder problem was back. They bled the system and said it wasnt in the transmission they put in and to try it.
The transmission is still shifting terribly hard, to the point where it has to be shut off at times and put into gear. Brought it to a local recommended transmission guru and he bled it again. It worked fine for him for a day and then the problem came back. He is mystified and doesn't want to just replace parts without knowing what is wrong exactly.