D-type OD engages with throttle off, disengages when even a small amount of power is applied. After 15 minutes of this, it works properly and can be switched in and out at will for the duration of the trip.

Details:
OD ran perfectly in my 1800. Instant engagement and disengagement, no kicking back out ever.

Tranny sat for about six months inside. Then swapped 1800-style cover for 122 cover, installed it in my 122 behind the same motor it used to be behind in the 1800. No appreciable change in power being fed to it or anything like that.

Switch, relay, all wiring is new down to the rubber boot on the solenoid. No possibility of engine movement shorting a wire. Connections are tight. Solenoid clicks fine in the garage, hot or cold. Solenoid is correctly adjusted. Filter is clean, entire tranny is clean, in and out.

As it seems to work once the oil heats up, that could indicate a viscosity-related problem. I have tried 80/90 hypoid gear oil, 30W motor oil, and 20W/50 motor oil. Makes absolutely no difference.

If something hydraulic were failing, it would not start working with hotter oil, right? If something electrical was funky, applying power shouldn't make any difference, right? Thought maybe the solenoid wasn't throwing far enough, but seems like they either complete the throw or burn up trying. It's not burning up and it's not blowing the (new) fuse.

I've already done enough speculation for all of us here, so I'd really appreciate hearing from someone who has actually seen a similar condition and knows what cures it.

Thanks!

--Phil S.

Not the lockout switch.

1) soldered new wire onto the solenoid, instead of new wire crimped on the stub of the original 37-year-old wire.

2) reflowed all solder on the end of the solenoid -- I think this may have been the problem: old slightly fractured joint finally connecting when it got hot.

3) burnished the contacts as long as I was in there.

Seems to work perfectly now.

8^)

Could be a sticking 4th gear lockout switch. You could always bypass it by directly wiring 12volts to the solenoid.

I've done this with my J-types before. I run 12volts from the fuse box to a switch inside the car then down to the solenoid thru the shifter boot. You have to worry about driving the car in reverse with the overdrive engage -> I hear it will destroy the OD (something about a one-way gear).

That's the first step I would do.

Paul

Although it may seem hydraulic, I get the feeling its electrical and has to do with the switch in the top cover for the tranny you exchanged. That is all that is different between the two applications that I get from your post. I did not dicern form your post if the tranny switch or the operating switch inside the auto is new.

Power routes to the solenoid through the tranny switch so the OD is only available in 4th gear. The switch may be slightly gummy and slow to move when cold. The heat from use loosens it up then it works correctly from that time forward. It may be slightly worn on the end inside the tranny where it contacts the linkage. The top cover may be bent or slightly out of position. Washer between switch and cover too thick. Heat expands everyhing and all works and tests normal as you try to locate the problem.

A small test lamp wired with the solenoid where it comes OUT of the tranny switch to inside the auto then to ground will tell you what is happening to the solenoid power during that short period it acts up.

Duane

I'm certainly no M41 expert but I listen to peoples stories every day so I can diagnose what is wrong with their appliances. When I read "Then swapped 1800-style cover for 122 cover", the 4th gear switch came to my mind as the possible problem as well.

Phil, please post back when you get it solved.




--
Bob W.
15 Volvos ('58-'91)
445-544-122-240-740

Low system voltage perhaps?
When mine was on a relay I had problems like that. Mine was a J type.
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma