Having major problems with the overdrive. Checked wiring, relay, and the unit itself, flushed the fluid. The car does not go into over drive. It does however work in about 20 minutes of city driving only, stop and go traffic. Once it works, it stays on through the drive. Otherwise on highway driving, my 30 mile commute, it does not work at all. Not good gas mileage. The car does have 350k miles on it.

I went through a similiar episode with my 90 last winter. It's a very frustrating problem. Especially in winter when climbing under the car is the last thing you want to do!

I did a lot of research on the BB about the problem, and although I'm no expert, what you say suggests to me that the problem is probably a bad wire that isn't always passing current, or less likely, a defective OD relay that works only part of the time. Both have been known to happen.

Have you tested the wiring with a multimeter or similiar? On my car, after a lot of work, I finally found that the wire to the solonoid from the shifter box was corroded. The wire was bad on TOP of the tranny near the back where the driveshaft bolts up to it. Only found it when I jacked the car way up and searched around in there. It was very difficult to see and find! You might want to check that spot since I remember others having the same problem with that wire.

Finally, have you tested or replaced the OD relay to see if it works with a different relay? Maybe obtain a junkyard relay and pop it in to see if that changes anything. It's worth a shot and you can probably return it if that's not the problem...


Good luck,
Jim
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90 244DL 263k :)

I think if you disconnect the driveshaft and the rear motor mount you get the OD solinoid out and then check the O ring on that. If replacing that doesn't fix it then it could be the internal piston o rings, which of course you would have to pull the OD off and disassemble to get at. With that many miles on the car I suppose you'd have to expect sealing to be an issue.

Try this first before you even think of going after the OD solonoid.

If I remember correctly, with the engine on you can test to see if the solonoid is getting current by opening your door or window and listening for it to click when you push the OD button on the shifter. If no click, no "juice". My car didn't click. So that told me that it was either an electrical problem or the solonoid was seriously gunked-up and wouldn't move!

BTW - The OD solonoid is last thing I would go after based on my personal experience - ie. my own OD nightmare! They rarely go bad.

But if you do decide to take it out, there is no need to disconnect the driveshaft or rear motor mount. You can get the solonoid out "as is" if you use correct-shaped (bent a certain way) wrench. I forget the wrench's name, check the archives. I believe Bob Haire mentioned it sometime ago.

It is, however, much easier if you loosen the tranny supporting bracket and let the tranny "drop" a little then go at it. If you do this, make sure you have something to support the weight of the tranny when it drops!



Jim
--
90 244DL 263k :)

When it does not work, does the orange light go on on the instrument cluster?

Be sure you clean up the fuse and fuse contacts for the appropriate fuse on the fuse panel. I use a tiny knife tip inside the holes on fuse panel contacts to scrape of corrosion at the point of contact there. Be careful! A small file or a Dremel tool bit (hand-powered) would be good too.

The brass/copper fuses are much better than the gray metal ones. I get the good ones from the pic-n-pull for not much money, keep them in a bag in the glove box for whenever needed. Clean them up with emery cloth, or with a knife blade if that's all you have handy.
--
Sven: '89 245, IPD sways, electric rad. fan conversion, 28+ mpg - auto tranny. 850 mi/week commute. '89 245 #2 (wifemobile). '90 244 (spare, runs).

No the light does not come on when the OD is not working. Yes the fuses and contacts are fine