Volvo Repair: 1982 Volvo Turbo Overdrive Problem, volt ohm meter, center vents

Question
Hi Regis:

A problem just developed with my 1982 Volvo Turbo, Automatic - the car refuses to go into overdrive.

When the overdrive button is pushed, two things happen:  the overdrive light on the instrument panel goes on/off, and I can hear the relay clicking on/off (only when the button is pushed).  I have checked the overdrive fuse, and it is fine.

I suspect one of three things:  the relay contacts are shot;  the solenoid has an open coil;  or the solenoid o-rings are shot.  Do you have any other ideas or procedures which can identify the problem more precisely?

Where exactly is the overdrive relay, and how can I best access it?

If I can get under the car to the solenoid, can I put a volt ohm meter across accessible terminals to check for 12 volts and coil continuity?

How long a job is it to replace the O-rings?  Is there anything else besides the O-rings that need to be replaced (i.e. gasket) at the same time?

Thanks for your anticipated assistance.

R. Michael West

Answer
first I would check for power to the solenoid and see if you can feel or hear it click if you do I would remove the solenoid and check the oil passages on the tranmssion for being clogged. I would use a small piece of wire to push into the holes to see if they are clogged.the solenoid and Orings arfe easy too do.
the relay is behind the glovebox .remove the glovebox and look toward the center vents you will see the relay.