Overdive for 4-speed `84 240DL Wagon

Hey all, 210k miles. Overdrive is working less and less.

I already gutted the relay. Overdrive is hardwired to a heavy duty
switch I pulled from something on the Apollo program. The overdrive
will enguage sometimes if its cold out. Once the car warms up it seems
less likely to work. If its like 60 degrees out, it sometimes will
enguage if I'm going 70 up a hill and floor it. Less and less likely
though. That used to be surefire.

We've replaced the tranny fluid ~30k ago. There's a magnetic filter we
clean fairly regularly. I think we even replaced the solenoid itself
like 60k miles ago. All these steps "felt" like they were making it
better, but for every one, 10k latter it was just as bad as it had
been.

It keeps getting worse. It used to enguage basically no-matter-what in
the cold. Now once the car starts warming up, it doesnt seem to want
to enguage.

I'd really like some advice on this. with a working OD, the car would
be great.

Rektide

 

Internal to the OD are two O-rings that after a hundred and sixty thousand
miles or so will start to no longer be able to contain the pressures
necessary to engage the OD.

Cold fluid is thicker than hot fluid so the OD will work when cold but not
when hot.

The only true cure is replace the two offending O-rings, whihc requires
removal of the OD from the tranny. The tranny can stay in the auto.

See:

http://www.brickboard.com/FAQ/700-900/OverdriveRebuild.htm

for a how to description.

Duane

 

There's a set of seals inside the OD unit, IPD sells a rebuild kit for it.

If you don't like the relay, you could always use the pre '81
arrangement with the heavy slide toggle in the shift knob, though I
personally like the relay better.