Ok, so this sunday I took a road trip up to PA to race 1/32 scale slot cars. Took my '71 142E up, OD was working fine all the way up, no hesitation or anything else to signify anything wrong. Get in to come home, and no OD. Driving 2.5 hours in a car without overdrive is not fun. Get home, test all the electicals, everthing is working fine. Change out the solenoid just is case, still no dice. Put the car up, pull transmission and dismantle the overdrive. Can't find anything blocking passages, and the pressure regulator thing (you know the one with all the springs and pots) seems to be in perfect condition and no visible issues. Reassemble, and still no oil pressure to engage the overdrive. What on earth is going on here? Its not that complicated a unit, and I'm pretty sure I didn't miss anything obvious.

Also, where is a good source for the internal seals for these OD units? I did a google search, and all I can come up with is info sites on the unit, but nobody with parts/seals for it. Thanks.

-Nick

OK, since you are SURE the electrical is getting to the solenoid through the 4th gear switch and not relying on the dash indicator (wired together with the lead to the 4th gear switch) to mean the OD is engaged, the only item left is the actuating piston seals accessable via the front of the OD once it is off the tranny.

A sudden failure of these two O-rings is possible although they usually exhibit a--work when cold but not when hot symptom--for a few weeeks or months before total failure.

Parts and seals for the J, or D. Takes a day to get and whatever time between here and there to ship.

Duane

Yeah, solenoid goes clicky with confidence. The last time (years ago) that the OD went out like this it there was an issue with the pressure valve, i.e. one of the dashpots (or whatever they're called) broke, so the spring couldn't do its thing therby regulating the pressure. Other than when the oil got low a few months back, no it hasn't been slipping or hesitating when engaging. Did find an awful lot of the clutch material in the filter, but it wasn't clogged totaly, and I cleaned it out anyway. Besides, if the OD clutch was wearing, wouldn't I have noticed some slipping similar to having a bad clutch when accellerating on the interstate?

Worn clutch lining would not affect acceleration since that is through the Sprag bearing for one to four gears. If in OD mode you would not notice the slippage since it would seem to drop back to 4th instead.

At this time most likely the actuating piston O-rings are not functioning.

Duane