1993 Towncar: Transmission downshifts randomly

Dropped the pan and replaced the filter... cleaned out the pan and re-installed. Wasn't very dirty. I've seen much worse. Didn't solve the problem. Wife drives on the highway and the right rear caliper blows smoke.... partially locked up. SPECULATION: The brake drag was convincing the transmission that the car was "going up a hill" (under intense load) so the tranny was downshifting to compensate. Rebuilt the caliper and replaced the brake hose. Adjusted the parking brake shoes. Transmission is okay for a few days, then it starts all over again. Didn't re-check the caliper yet to see if it was locking up again. Anybody have any input on this? It's intermittent. Can ABS cause this? Or is it really a transmission issue? (I'm on a witch hunt?)

I would check the wiring to the VSS on the extension housing of the transmission, if it's ok you'll need to either have it scanned with a PID capable scanner to check the vss readings; it might have gone bad...

Oscar.

Dropped the pan and replaced the filter... cleaned out the pan and re-installed. Wasn't very dirty. I've seen much worse. Didn't solve the problem. Wife drives on the highway and the right rear caliper blows smoke.... partially locked up. SPECULATION: The brake drag was convincing the transmission that the car was "going up a hill" (under intense load) so the tranny was downshifting to compensate. Rebuilt the caliper and replaced the brake hose. Adjusted the parking brake shoes. Transmission is okay for a few days, then it starts all over again. Didn't re-check the caliper yet to see if it was locking up again. Anybody have any input on this? It's intermittent. Can ABS cause this? Or is it really a transmission issue? (I'm on a witch hunt?)
Check the gear selector mounted on the drivers side of the transmission. It's a black plastic thingy that hooks up to the shift lever, and it should move silky smooth. Mine was full of water and it caused the car to downshift randomly @ highway speeds. Replaced it and all is fine now.
Just something to check.
Mike

Thanks .... I'll check those items.