TSB# 97-11-11 for 4R70W tranny states. Erratic or prolonged 1-2 shift.
94-97 Mustang and others. Replace the cast aluminum piston with the one piece
stamped steel piston with bonded lip seals and replace the top accumulator
spring. This is due to 1-2 accumulator bore scuffing the revised piston can be
used in the scuffed seal bore.
This may be your problem.
Tuesday, January 22nd, 2008 AT 10:00 AM