Sounds exactly like the symptoms my '85 had when the 4th gear switch went. Costs about $30 at the dealer. R&R isn't a lot of fun so I recommend you get a new one. You don't want to do it again.

Put the car on jack stands as high as you can get. Loosen the exhaust joint near the transmission. Support the transmission on a jack, remove the bolts from the cross member and lower the transmission as much as you can watching for interference in the engine bay. I used a "crow-foot" and flex joint on the end of my socket set extensions to loosen and re-tighten the thing. (Pull the electrical connector of course.) As I remember there are two switches, the other being reverse? This is the one located on the forward, top right.

Mine used rubber spring elements which had degraded with age and oil. They also obviously got very temperture sensative.

Go to or call the nearest Volvo parts supplier and get thee an OD 4th gear switch for the transmission. Then with a 14 mm socket and 22 mm medium depth socket and ratchet, and jack in tow, crawl under the right side of the car.

Place jack under tranny. Remove the two trans support bolts from under the drivers butt and reinstall them three full turns. The release the other two bolts from under your passenger seat. Lower trans until it rolls slightly to the right, enough to get the 22 mm socket on the switch.

R&R switch. Reverse above process tightening all bolts. Drive happy.

Duane

Mike,

Check the fourth gear switch first (the one in the transmission). These switches become worn and cause a loss of overdrive, especially when cold. Being worn, the contacts in the switch do not make contact with the internal parts of the transmission. Once the metal in the tranny becomes warm (and therefore expands) the switch makes contact and allows the overdrive to engage. When this switch is bad, the conditions you described will arise (no OD when cold, no light or relay click). The switch in my M46 is the same way, but worse. I have no OD at all during the winter, but it works great during the summer months. Anyway, this is most likely the cause of your overdrive problems. Good Luck!

P.S. - Anyone out there know off hand what these switches cost? Thanks...

No doubt start with the resolder of the OD relay. Check fuse.

Have you "flushed" the fluid and dropped the little screen?

Could be a funky 4th gear switch, OD solenoid or possibly the OD switch itself.

Mike,

Nice car. How many miles?

I would check the OD relay first. Drop out the glove box (few easy screws) and I believe that it is to the left. Can't remember if it is orange or white on a stick. The solder joints in the relay can become brittle with age and work intermittently or not at all. The relay can be resoldered or replace. Resoldering costs $0 and take only 15 minutes, so I would try that first.

Don Foster can provide you with pics that show where the relays usually fail and require resoldering.