HELP!! A4LD in 93 Mustang slips badly in reverse when warm

[goofyfoot53]

HELP!! I have a 93 Mustang LX 2.3L auto with 85k. I installed a TransGo shift kit to the letter, according to the instructions. While it solved the stalling when put in gear problem, now it's very soft and slow going into reverse when cold. Once warm, I can't feel it go into reverse at all, but apparently it does shift since it moves back when I apply throttle, but it slips a lot, requiring me to rev it more than I feel comfortable. I've started parking where I can roll backward or drive straight forward. Before I had the stalling problem, it shifted into reverse very firmly. A bit too firmly, in fact. I called TransGo tech support, but they had no answer. The tech guy suggested changing the TransGo spring on the reverse servo back to the original spring to see if that would help. Of course, that would require draining all the fluid and dropping the pan again, which I really don't want to do without knowing for sure that is the problem. In addition, the Mustang is my only working car right now because my other vehicle has developed a severe oil leak, to the tune of over a quart of oil when I take my wife to work, a 12-mile round trip. I believe it's the timing cover gasket, which is a lot of work to change. Btw, it doesn't slip at all in any forward gears. Any ideas?