I've done that math already, there's about a $200 difference, assuming the OD is the only reason I've lost 4.8 MPG since September. I just can't imagine any shop opening up an automatic for anywhere near $200.

 

Just to update the thread, should anyone else have this problem:

My retired ASE mechanic uncle, based on all the stuff I tried, is 99.99% certain it has to be a dead solenoid. This is a conclusion based on the fact that applying power directly to the solenoid did nothing, and the trans is displaying no other issues of any kind. As a result, I took it to my usual shop for a quote, and their software spit out 1.5 hours total labor. With the parts I could be out from under this problem for less than $300, which is amazing. Dude even double checked that he had the right job up, and that was it.

I'm debating keeping my shutoff switches, though.

 

The PCM should whine about a failed solenoid though...... If it requests O/D, and doesn't see the requisite RPM drop, the code should set.

 

Wouldn't be the first code the pcm has failed to throw. It took it months to notice it wasn't regulating my voltage anymore.

​​​​​​I'm trusting my mechanic uncle's judgement, really, I don't know enough to stake an opinion. He's had a few of these apart and is of the opinion that if there were a mechanical issue in the transmission, it wouldn't only be affecting the overdrive.

I will, of course, update the thread regarding the outcome of the repair.

 

If you look at the fault codes for OBD1(2 digit, pre magnum) there isn't any regarding the pcm not seeing rpm drop when in od. As long as it's seeing the solenoid hooked up(and not shorted) it's not going to throw a code working or not. Back then OD was an option so guess they didn't put that much thought in it.
https://www.allpar.com/fix/codes/index.html

 

That does make me feel better, thanks.

One more week of taking the back roads at 45!

 

Wow, that's enlightening. Thank You. I suppose, if there isn't a code to set, it won't set one. There isn't anything in there talking about O/D at all..... so, it doesn't really matter what failed, the PCM won't report it.

 

Yeah, the only codes it's thrown related to the OD are when I unplugged the thing. I wish it threw a code, I would've caught it sooner than 2 weeks before a road trip, but most of the time I'm on the highway for more than half an hour I have earplugs in and music going. Oops!