My '86 764T6A just hit 150,000 miles and is showing all the signs of a faulty O/D solenoid. Is this replacement difficult to do? The FAQ seems to talk extensively about avoiding the introduction of dirt into the tranny, which should be a no-brainer to anyone working on a transmission (or just about any other part of a car, especially an old car). I don't have a garage as I am a poor college student and live in an apartment complex. I do have a large, reserved, level parking space. Will I be able to replace the solenoid here, or should I pay for a shop to do it? Any input greatly appreciated!

Follow the advice of the other post and make sure you don't just have a bad relay. They are much easier to replace, and many times you can just resolder the connections of the relay and fix it for free.

Assuming it is not the relay, replacing he solenoid is an easy job that you can do in the lot. Heed all warnings about dirt. The OD solenoid sits on a ledge on the side of the transmission and this is a fine place to collect dirt, etc. I would use a stiff bristled brush (need a new toothbrush) to remove all the crud around the solenoid, then spray with carb cleaner or the like and brush till clean. (I buy the cheap stuff, from Wallmart for just such purposes.) When the exterior of the old solenoid and transmission is clean, you just remove two bolts holding the solenoid and lift it up. There are a couple of clips holding the harness also. I would get the wiring loose first. I removed one from a 240 recently, and had a tougher time with the wiring than the solenoid itself. There was a wire tie near the top of the transmission and I had difficulty getting a pair of cutters up there to cut it free.

Replace two o-rings where the solenoid connects to the transmission.

You could try a local self-serve junk yard for the replacement. The cost should be low, and you will get practice removing the solenoid.

One last and most important item: Use ramps or jack stands to spport the car while working under it. A crushed brain makes studying really difficult.

Dan

Thank you, this is all extremely helpful.

I of course verified the relay's proper operation, in fact, it looks rather new. Also, the light on the dash seems to be working fine, as it comes on when I press the button, but when I press the button again and extinguish the light, the trans still stays in 3rd. It does eventually go into OD, but it can be as long as 10-15 minutes. Other times, it works fine right away. There is plenty of fluid, and it is in good condition.

I have noticed other problems with electrical wiring on this car, and am frankly quite disappointed. I never had electrical problems on my 240, and I'm wishing I had a nice 244GLT instead of this car.

Thanks again for your helpful insights.

PS, the Haynes manual for this year only discusses the overdrive unit on the MT. Does anyone know if the overdrive unit and/or the procedure is the same on the AW71?

Replacing the solonoid is not difficult at all, it is just a bit cramped. A short stubby wrench will do it (10mm I think).

What are your symptoms? What is the red light doing? Assume you have already resoldered or replaced the OD relay which is far more likely to be the cause.


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David Hunter

Replacing the OD solenoid on a AW71 is not hard, it can be done in a driveway if you can get the car up to get under it. Be sure to support the car properly with jack stands, and block the rear wheels. My local dealer wanted $240 for this solenoid. I found one used for $40, still working fine after 2 years. Test yours first. Remove it and apply 12 volts; if it clicks it is fine, and the problem is elsewhere, e.g. the relay or the wiring. Get to know some sources for used volvo parts. I, along with others, recommed Brian Leppin at volvousedparts.com. However, there are other good sources.

regards,
Mark