I picked up a 1985 740 turbo intercooler in LA, 260,000 miles. lots of stuff rebuilt or replaced, including the transmission at 259,000. I think it was used - the previous owner - a woman is a little vague on this. The car runs great, has lots of power and I drove it around in so CA for about a 1,000 miles, then took it across the mountains from Tamecula to Indio headed for phoenix, AZ. ran like a song but as I came out of Indio and started up the long 17 mile hill - no a/c although very hot 108F, the overdrive suddenly disengaged, then engaged again, then disengaged/engaged several times and then finally wouldn't engage again despite the green "5" light came on.

I drove to Phoenix at 3K RPM = 58 - 60 mph, got 25 miles to the gallon, pretty good I thought though I've been getting 28 average while in CA with the OD working..=*^)

Now, a week later, still very hot here - and the OD won't work. Same thing, the light comes on but no 5th gear. I don't live here so don't know any Volvo guys and wonder if any of you guys have an idea of what's going on here.

I am seriously thinking of restoring this car. Got much new stuff and as I mentioned the engine is very strong...

Any help would be highly appreciated (also hints on how to take the dash apart - the selectors for heat or A/C is stuck in defrost (new A/C compressor)...=*^)

Christer

Hello from Tahiti

You can first check the relay for OD on the fuse box from of the gearshift
it's normally red on the right side
Secondly you will have to check the wire that goes to the SOLENOID VALVE mount on the left side of the gearbox under the car
Third you will have to replace the SOLENOID VALVE

Hope that this will help you where you are

On the road again with VOLVO

VOLVO FOR LIFE

One last point
you can check the button on the shifter
maybe its leakage

For the wire check from the shifter to the SOLENOID VALVE and not from the SOLENOID VALVE to the gearbox

VOLVO FOR LIFE

Hi Guys,
Following on from the advice given above, which is sound advice.
Here is my piece of advice: -
I have had similar problems with the OD I checked as listed by other members, however I decided to 'have a go' at the relay, it's the big yellow one marked M40.
Located in the centre tunnel under the radio.
I gentley took it apart (replacements are very expensive here in the UK) all seemed well, I drowned it with WD40, shook the access off, replaced the cover, reinstalled it - low and behold it works a treat.
Todate it hasn't NOT worked despite abusing it to try to make it NOT work.
This may not be the solution to your problem BUT just might be.
Best 4 now -=- dustyv