i have a 92 bonn se when on the freeway for an hour or so the rpms will be @ 4000 and speed @ 65-70 it wont shift into 4th on occasion i can let off accelerator at 65-70 and it will shift into 4th please help"fluid level is good"

Vacuum modulator may be bad. Cheap fix vs transmission replacement or rebuild.

thank you im going to try that