Hi everyone,

I hate to post on such a common topic (it seems), but I need some advice.

Here's my situation:
I have an 82 volvo 245 with manual trans. The overdrive works sometimes. Most of the time not. The button is connected. The light is never on. I've only ever seen it once.

To further complicate things, my odometer was not working, so I took apart the unit and fixed a broken gear but screwed up my speedometer in the process (messed up the tension spring on the needle- is that replaceable?). Now my odometer works, and the speedometer needle does go above 40 or so. Would the speedometer keep the overdrive from engaging? (see excerpt from manual below)

I am planning on replacing the OD relay, but want to get your perspective before buying. What do I need to do to fix this thing?

Thanks!


<<<from the manual:>>>
Overdrive (some models only)
Shift to overdrive at 45 mph (70 km/h) and disengage it when speed drops below 40 mph (65 km/h) or vehicle encounters hilly terrain. The overdrive can be engaged in 4th gear only. The overdrive is engaged by pressing in the switch on the top of the gear lever. If the switch is pressed in once again the overdrive will be disengaged. In addition, the overdrive is disengaged when downshifting.
No extra operation of clutch or throttle pedal is normally necessary. Engagement is facilitated if the accelerator pedal position is maintained steady.
When disengaging, depressing the clutch pedal slightly makes a smooth transfer.
The overdrive should be used after the engine has reached normal operating temperature (minimum time is five minutes) and the vehicle is being operated on relatively level roads.
Downshifting to a lower gear will disengage the overdrive.

This post only relates to manual transmissions.

see:
http://www.brickboard.com/FAQ/700-900/Tran...asicDiagnostics

For the electrical part:
Make sure fuse 11 is clean. The solenoid in the OD unit has to be powered for the OD to enguage. You should be able to turn the key to position 2 and push the OD button on/off and see ~12VDC coming out of the relay on the yellow wire while in 4th gear (not running). If you do see 12V that would suggest the relay is good, but you still could have a problem with the wire under the car or the solenoid itself. Also, the red wire has to be grounded to tell the relay that you are in 4th gear.

I don't have a manual trans. but I bet if the solenoid is working you can hear it click on/off under the car while not running (in 4th gear) with someone's help.

The mechanical part:
fluid level and quality
pumps, pressures, seals, etc

I had a similar problem with my overdrive having a mind of its own few years ago.

Problem: Basically the overdrive light would turn on when I start the car and the transmission would not shift, even if I preseed the overdrive switch for ever. It turns out that it was the overdrive relay and it was easy to fix, I just had to resolder the overdrive relay. Apperently the soldering cracks overtime and it fails to function.

Solution: remove the overdrive relay. Pull the plastic cover housing the relay board. Use sodering iron to heat any cracked joints. You can use an ohmeter to measure connectivity before and after soldering.
There was a good website that walked you through the steps but I could not find it now. Anyway, here is another website that explains about the cracks:
http://www.volvoclub.org.uk/faq/Electrical...e_Panel_Removal
scroll to "Repairing and Resoldering Relays".

That is a great link. Thanks a lot. I haven't had a chance to touch it in the last week. Hopefully I will get to it soon. I'll post more if I have q's.

Thanks again to both of you!

So I re-soldered a number of the components on the relay board. What a great idea. I had no idea it would be that simple or easy!

It works better than it ever has.

One problem:
I still have my glove box out and I took it for a test drive. When I hit the button and overdrive kicks in, the relay buzzes quite loudly. Is that normal? Should I worry about it?

Once the glove box is back in and the relay is tucked behind the center console, it might not be audible, or at least very audible. But i would love to know if anyone has some experience with this.

Thanks!

-dan