hello. i have a 1986 Toyota pickup. it will no shift into overdrive.

Toyota-uses the coolant temperature input signal to control the Overdrive operation, have the sensor checked hot and cold

thank you but where is the sensor located?

When OD button is depressed, does the OD-OFF light comes on?

yes it does but the trans does not shift?

Also check the throttle and vehicle speed sensors-scan the computer for code/s

If the tran is not shifting into overdrive but shifts normally for all othere gears, have the overdrive solenoid checked. Quuite often the solenoids gets stuck and woould nto shift. It might start shifting again after some running.