I have a 1987 740 Wagon,auto trans, and the overdrive is wacko. I think it may be an electrical problem. Sometimes the relay clicks sometimes not. The overdrive engages automatically 90% of the time. But, 10% of the time it doesnt. Ill be accelerating on the highway and it will either not shift into 4th or it will shift into 4th but then jump out back to 3rd. When it doesnt shift into 4th, I can wiggle the overdrive relay and it will click and shift into 4th. I checked out the wiring under the overdrive relay and couldnt find any obvious shorts. I took the button on the shifter and the wires seemed ok. Does anyone think it is 1. wiring in the shifter or at the relay or fused. or 2. the wiring at the overdrive solenoid. Right now it seems ok. as long as i dont push the button on the shifter it will be ok for a week or so. this is annoying. Also does anyone know if its possible to wire the overdrive so it will automatically engage and bypass the buttom crap. thanks! Ken in Santa Barbara.