Dead Overdrive - '88 240 Automatic

We're driving three 240's: '83, '86 and '89, all with automatic transmissions. I've worked through a few problems with OD's.

Volvo OD's are very reliable, but the support electronics have various places where they can fail, and I certainly wouldn't trust the first mechanic who looked at it if they end up with a decision that you need to do a huge job. The OD transmissions themselves don't fail very often.

It's possible (I believe) that a deteriorating (nearly broken) wire between the gearshift box and the relay or OD solenoid could be causing the failure. As I recall, the wiring runs from the thumb switch to a relay located to the left of the glove box, and then back to the hump-mounted shifter housing. From there it runs out through the box, along the side of the transmission, to the OD solenoid. My wire had so much wear in the shift box - from years of shift lever movement - and also on the outside, along the side of the transmission, that it just deteriorated. It worked intermittently and unreliably until it finally just broke.

It's also common for the relay to fail, you often can get to it by removing the glove box (about 8 screws visible when you open it's door). It's to the left of the glove box, behind the center console. It's easy to replace. The part is pretty inexpensive, unlike the transmission-mounted solenoid which costs sume real money. But I believe that if your OD light is working, that indicates the relay is OK.

If you're adventurous, check out the wiring and - if knowledgeable folks say it could be dead, replace the relay. And definitely see a second mechanic if it's still not right. Don't give yup on the transmission itself, the problem is likely somewhere in the support electronics.

A mechanic friend of mine says you can permanemtly lock in the OD function by re-engineering the solenoid. It still kicks in as usual, and downshifts if you stop on the gas. You just can't lock out the solenoid via the switch if you do the deed. It needs a hole to be drilled inside the solenoid.

Bruce

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Michael Cerkowski wrote:

I was hoping that was the case. When they do fail, what are the symptoms?

Yes, the light goes on and off with every single click of the switch, and I can also hear the relay click. I think it's solenoid-related, or a dead O/D.

I did find a reference on the Net to the solenoid getting filled with metal dust, and refusing to disengage. I wonder if this can also cause it to not engage properly...?

Not interested in that. I do appreciate the response, though! How do I go about diagnosing the engagement solenoid? I actually plan to have another shop look at the wire to the transmission and the solenoid, but I would like to be able to give them explicit instructions. I'll check the wire in the shifter housing myself, first, I think.

The dealer is correct!! If he replaces the trans, the OD will start working. Of course he will have to fix what's really wrong to get you to pay for the unnecessary transmission.

I had the same symptoms on my 86 240. If the OD light dosen't it is probibly either the solenoid or the wires to it. TRY this:

• Run a fused line directly to the sol. If it works fine it's the wiring. If not it is the solenoid.

Overdrive (fourth gear) works when the sol picks up and lets oil flow. A solenoid is an electro-magnet operated valve. The coils usually fail by shorting out internally. These turn-to-turn shorts reduce the number of turns in the coil and the magnet gets weaker. When the one on my 86 240 failed it would work for a while, then drop out after it heated up.

OD Solenoids are expensive, $150. I bought a "New" one from an unnamed Volvo dealer in West Palm Beach. The package was opened and the "O" rings were missing, but it couldn't be a return because they don't allow returns on electrical parts. Well I was desperate so I took it anyway. It fixed the problem.

But when I took the old one out, I realized that I didn't need a new one. I live in flat south Florida. I never turn OD off. Next time I will * Cut off and tape the wiring. * Throw away the inner O ring. * Cut (grind) a groove between the two holes * And re-install the "repaired" solenoid.

That will bypass the solenoid and I'll have a 4 speed.

Do you ever take it out of overdrive? If not, Bypass the solenoid and forget about it.

Al

Had 79 245 D, 81 240 D, 86 240 320,000mi and running fine when traded 94 944 Green 257,503 mi CRUNCH Parted out Have 94 944 White 149,000 The New one 94 944 Maroon 135,000 mi

I can't figure out your line " If the OD light dosen't it is ". Do you mean 'if

the O/D off light works ok, it's the solenoid or wiring'? Or that if it *doesn't* light, it's the solenoid or wires...?

Is the dreaded Haynes manual going to show me which terminal I should connect the hot wire to? I haven't dug it out of the (cold) garage, yet. That does sound like a good way to test it, although I assume I should also disconnect the wire from the relay, in case that wire is shorting? Otherwise I'll just blow the fuse...

Thanks. I know what a solenoid is, but didn't know exactly how it engages the O/D. I haven't actually tried it again - maybe I'll see if it works when cold.

We do use it occasionally to descend a steep hill in Winter. The hill is on most of the routes we take. Thanks for the ideas and explanations.