I've eliminated (I think) everything other than the gear sensor for why I can't get into overdrive. It's tough to reach that from under the car, though.

What usually goes wrong with it, and what is the best way to get at it?

thanks,
john

4th gear switch replace. Gain extra clearance by placing a jack and support board under tranny, jack to take weight of trans.

Remove and replace three full turns the left side trans support cross member bolts. Remove the right side trans support bolt. Slowly lower tans with jack until you can reach the switch. When the trans support hits the left side bolts still in the body, further lowering will "roll" the trans down to the right opeing up the access space. Go just far enough to access and replace the switch.

When jacking the trans back up, us a long drift or similar to guide the right side bolts holes back into position. Torque support bolts to specs.

Duane

I had to change mine out on my 82 245 and found it was easy to take out. The switch is located on the passenger side of the transmission on the top. You will find a single wire there. The replacement has a longer nipple for the wire so it was more difficult to install with the socket that I use to take it out.

I swapped mine out with the aid of a deepwell socket that I grasped with a large set of ViceGrip pliers.

Randy

I got it out with a small volume breaker bar (no room for a socket wrench head) and a 7/8" long socket, as I recall. I did not lower or undo anything. The car would not always go into OD, especially when cold. Totally fixed the problem.