Well, my tranny failed 2 times actually on a 4.4 with 123k miles 1st time. I don't exactly know the names (first one was driveshaft or something like that. Long metal piece was broken and gears were screwed inside as I was told) However they fixed it for 400$ and works like champ. Seccond time after big stress on it broke (some kind of clutch, round metal thing moving one side and locking other) and it would move freely. 300$ for that. and works great now. Although after stressing it I do feel some sluggish changing, Thinking of changing oil and filter in it now.