I have a 40 ford coupe w/ 700R4 Trans. will not shift into 4th gear don't think it is going into lockup either. No computer, manually shifts into 1st, 2nd,3rd put in drive and will not change stays in 3rd. Have changed pressure switch, lock up wiring all from GM. Removed valve body no sticky valves. TV cable was ok tried several adjustments. Had it rebuilt completely when first installed have 19000 miles on trans has been working fine up until now. Don't know what else it could be.
Thanks in advance