i have a 1984 240 DL with an overdrive that seems to have a mind of its own. when i got the car the shift knob was off. i took the switch out and hooked it up to the wires on the shifter. on the highway it will usually shift into OD no problem. sometimes i get nothing though and sometimes the light will flicker on and off several times accompanied by a buzzing sound and then it will not work at all. when i take it out of overdrive, the light goes off but it does not shift out of OD for approxitely 1 mile after, then it shudders out of overdrive. i have no idea what to make of this. relay? maybe a fourth gear contact? any help would be appreciated. thanks -tim

I would go ahead and replace the fourth gear switch. Mine went crazy so maybe yours is gone too. What you could do to test the relay is "pretend" the fourth gear switch by grounding its contact on the relay. OD wiring diagrams are on:

www.geocities.com/janicerennie/pictures

If you still have problems, wait till someone tells you how to resolder the relay, or buy a new one. Check the 700-900 FAQ for that.

Check everything before delving into the OD unit itself, although maybe checking the contacts on the solenoid is a good step.

Rene