After first making sure the fuse is good, and the tranny is full of fluid...

The key to finding out where the true problem resides is the dash light that indicates when your are in "5th".

If the dash light goes out when your tranny goes out of 5th, the trouble is with the 4th gear switch or the relay. If the dash light does not come on when you push the button, add to the above the switch on the stalk. 99 percent of the time it is the 4th gear switch.

If the dash light stays on or comes on and you do not have the overdrive, check the wires to the solenopid first to make sure they are clean, tight to the terminals of the solenoid, and no broken wires are hidden by the insulation.

How? you ask. Vehicle stopped, engine OFF, ignition ON, shifter in 4th, door open and your head next to the door sill, push the button on the shifter. If you hear a click from under the car all is well electrically. No click heard, look at the dash light. IF off 4th gear switch, relay, or stalk switch.

If you hear the clickj fromm under the car, and driving does not yield Overdrive, the overdrive is in need of actauting piston seals.

Duane