Intermittent DTC 81 on 1995 GMC K2500 w/ 4L80E

I have this intermittent problem . . . I start the truck,. put it in gear and it is only in second. I can stop the vehicle, turn off the key, and usually it will then be OK. Happens maybe 10% of the time, and only happens
when I start the truck - doesn't get stuck in second gear just driving or from a stop, etc.
I have had the following done by the dealer and/or transmission service company: Replaced 2-3 Solenoid Replaced all solenoids. Replaced valve body (three times) Replaced internal transmission wiring harness Replaced PCM Dealer checked ignition switch, said it was OK. (At some time, you have to jiggle the key to unlock the switch and be able to turn the key)
Any suggestions as to what to look at or do next besides pull the rest of my hair out? :[
Dave
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Only way to find this is to check for power at the harness to the solenoids during the event, could be a bad ign sw. ( not the key cyl). BTW I would drop this back in the lap of the people you paid to fix this problem.

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