Hey Everybody, I was driving to work this morning going over a bridge with those expansion joints . I was traveling at about 59-55 mph and after hitting the bump the overdrive kicked in . I was able to turn it off with the button . Do u think it could be a faulty relay ? A bad button ? Is there a way to permantly leave the overdrive off because I never use it ever ? It's a 93 240 with 185,000 on it and all other electirical seems fine ! Any suggestions would be great ? Don't want to blow my tranny on the highway ! Thanks..

Loose connections at the transmission or loose wires to the relay etc.

when u hit the joint, the transmission down shifted right? If so, your OD was actually disengaged bringing you to 4th....so when you pushed the button...you were back to 5th gear....
If you knew this, disregard...and

CHECK YOUR TRANSMISSION MOUNT AS YOU MAY HAVE IT ALL SMASHED OR MISSING AND CAUSING STRAIN ON THE TRANNY....BUT YOU NEED TO TRACE THE WIRES TO THE TRANSMISSION AS A CHECK MEASURE.

OD RELAY IS ON PASSENGER SIDE BEHIND THE AC **** ....WELL A LITTLE BIT UP AND CAN BE ACCESSED TAKING OFF THE PASSENGER PLASTIC COVER....LEFT LEG SIDE...I ALWAYS HAVE ENCOUNTERED A "WHITE" RELAY....

^^^ No, I think it is from 3rd to 4th. As far as I know these transmissions don't have 5th. It is basically a 3 speed with OD for a total of 4 speeds.

Exactly! He was in 4th (OD), and it downshifted to 3rd, the light came on...

A jolt can trigger the switch. If it doesn't happen too often, I wouldn't worry, otherwise I'd look at the switch.

The Cruise Control acts similarly, disconnecting sometimes after hitting a bump...

That's exactly what it did from 4th to 3rd, I have to agree I think it may be the switch . It feels a bit worn and spongie . It does not really make any clicking noise when pushed . I changeing that button something I could do myself ? Thanks, Vince

the buttons dont click. light on means NO overdrive. lightoff means automatic OD (4th) as needed. bump activating light could be wiring or relay... does the button toggle the light normally?

Yes it does , occasionally it just illuminates when I start the car and it was not on when car was turned off . Hoping it the relay , seems like an easy fix .

relay is easy, but its more likely the wiring to the button, which is threaded up the shift lever, and kind of a bear to get at and replace.

I had this problem with my 740, every so often I could smack the side of ash tray that the relays sit behind and my OD would turn off. Switched out the relay and problem solved

I also had this problem and it was the relay.

It happens to me sometimes, but I noticed it isn't the relay, @ times I hit it with my knee without noticing. Since you were in a bumpy road, thats more likely what happened. LOL