4l80e overdrive drops out after 1 mile.

93 6.5l turbo Chev 2500. recently the oil cooler line rusted through, lost some oil. oil level looked ok from dipstick. drove home and took to shop next day, oil lines were changed, noticed that after about 10 miles the overdrive cutting out. scan code said B solenoid grounded. took it home, changed A and B solenoid, wiring inside looked ok, now the overdrive cuts out after 1 mile. checked the connector and found fluid on terminals, washed it with contact cleaner and put 0 ring around terminals to keep them dry, problem still persists.
tranny oil and filter and TPS was changed about 2 years 15,000k ago.

any ideas?

Anymore codes after the solenoids were changed? I may not be much help with your '93 because GM installed a different computer in my '94, but i notice with mine that if i brush my foot over the brake pedal while i am driving, it will come out of overdrive. See if the brake light switch is touchy like mine.

Thanks for the suggestion, Warren96, although I didn't find the brake switch to be a problem, I took the truck out for a long drive and no problem with overdrive kicking out after it sat for about a week. I am wondering if changing the A and B solenoids did it, or if putting the O ring around the contacts of the pass through sealed out the transmission fluid leakage. I have been driving it for about 150 miles now without a problem, but I also haven't stomped the fuel pedal yet. I don't understand how ATF would be conductive enough to short a 12 volt signal, but there's been a few comments about the connectors on the 93 and earlier 4L80e leaking, causing bogus codes to appear.

ATF is not significantly conductive. Electrical components have been submerged in the stuff for decades. However, if you have a leak/weep, the dirt/dust that is attracted to it can be conductive.

On the early models, touching the brake pedal (or otherwise closing the brake switch) will cause the TCC to unlock. This may seem like shifting out of OD in many cases. If the brake/TCC switch is too touchy, it may present itself as a problem, in an otherwise normal condition. The TCC is controlled by the EPA, so you figure out why it does what it does, when it does, and get back to me when you have an answer. I can only speculate as to their intelligence, or lack thereof.

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Originally Posted by DmaxMaverick

The TCC is controlled by the EPA, so you figure out why it does what it does, when it does, and get back to me when you have an answer. I can only speculate as to their intelligence, or lack thereof.

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Ha! That's the best explanation of TCC I've ever heard. And quite true.

Casey