I am a service writer for a Chrysler dealer and I have a 1988 Rx-7 non-turbo auto trans 4speed I've been trying to find a solution to why the Transmission will not shift into 4th O/D. I performed the TSB off alldata and it did not fix, installed new O/D cancel solenoid did not fix. Nothing burnt and nothing appears wrong with valve body, bands etc. Anyone have any ideas?