240 d wagon 1988 overdrive stuck

v-ride · Post by **v-ride** » 16 Nov 2009, 07:44

I was driving on the freeway and my car shifted into overdrive all by itself. Before this happened i could feel the shift to OD whan i pressed the button on the shift handle. I pressed the button when that happened but i could not feel the shift to overdrive. Now when i press the button, i get no response. i want to know if there is a way to fix this problem and if driving in continuous OD ,especially at highway speeds, will cause harm to my transmission?

FCPEURO · Post by **FCPEURO** » 16 Nov 2009, 10:05

I don't think it would harm the transmission overnight, but I would not drive it like that for long. More then likely, the relay just went bad and it stuck in the on position. Try removing the relay and see if the overdrive turns off.

luke_jones · Post by **luke_jones** » 17 Nov 2009, 10:20

Maybe I just don't understand the OD in our cars (since mine hasn't worked since I got it...same thing no response from the button on the shifter) but why would it hurt for the OD to always be engaged "especially at highway speeds"? I would think that the prime time to use it is at highway speeds.

Forgive me if I sound like a retard or a jerk, but I'm just trying to understand because I need to get mine working as well.

Post by **billofdurham** » 17 Nov 2009, 11:26

v-ride, welcome to Matthew's Volvo Site.

my car shifted into overdrive all by itself

What do you class as shifting into overdrive? On the 240 overdrive is actually 4th gear.

The transmission will engage 4th gear automatically after upshifting through first, second and third gears unless the disengagement button on the side of the gear selector knob is pushed. When the button is pushed to disengage 4th gear, the transmission operates as a 3-speed unit. If the button is pushed while 4th gear is engaged, then a downshift to 3rd gear will occur. The transmission, then, cannot upshift to 4th gear until the button is pushed again. As a reminder, when 4th gear is disengaged, the indicator light in the instrument panel is illuminated.

Is your gearbox driving continuously in 3rd, which is not overdrive, or is it in 4th, which is overdrive?

luke_jones, you are correct. Overdrive is intended for highway driving and is the most economical way to do it. If you aren't getting any response from the button it could be a fuse, relay or overdrive solenoid problem. If you aren't the original owner it is possible that the overdrive solenoid has been replaced by one of these.

Bill.

v-ride · Post by **v-ride** » 17 Nov 2009, 12:14

Now that you mentioned it that way, i believe my car is operating in third gear. I think it fell from 4th down to 3rd since it happened while i was at highway speed. Is there a way to disengage the OD? Also will driving in 3rd gear at highway speeds (65mph) harm the transmission? I'm doing it 5days a week now?

Post by **billofdurham** » 17 Nov 2009, 15:29

Is there a way to disengage the OD?

If you are in third gear you aren't in overdrive so what you want is a way to reinstate it, i.e. get back into fourth.

Check fuse #11 which controls the overdrive. Also check the overdrive relay which is located behind the dash just to the left of the glove box. Give it a hard flick with your finger. If it is stuck this may be enough to get it going again.

Also will driving in 3rd gear at highway speeds (65mph) harm the transmission?

Over what distance? The gearbox will take that in the short term. One of the instructions for using your transmission is to disengage the overdrive when towing or ascending/descending steep hills. You will notice a difference in fuel consumption as third gear gives a reduction ratio of 1:1 and fourth gear gives a reduction ratio of 0.69:1.

If the fuse and relay are OK you may have a faulty switch or a wiring fault from the switch. If you don't intend towing with the car then you could fit an IPD overdrive solenoid by-pass as detailed in my previous post. Otherwise, failing an electric fault, you would be looking, possibly, at replacing the solenoid.

Bill.

Post by **Jeff1964** » 29 Jun 2012, 17:55

Our 1986 240 will go to overdrive only when it is cool. Late afternoon, even late morning, and it stays in 3rd gear. I think my solenoid is fine. It started happening after a run up a hill on a hot day.. Could it be the internal workings of the tranny? (280000 + now)