TC lock/unlock and occasional downshift to 3rd

[rotohead]

Long time member here and hope I can find some help. Have the annoying lock/unlock with a occasional downshift to 3rd momentarily. I can switch my lock out switch to force 4th lockup and that works always. So it's probably easier to say what I'm mostly sure IS NOT the problem.
It's not a AC volt issue.
I've changed the electrical components (OD solenoid, gov and transducer, springs, etc) twice in the last 10,000 miles.
VB is a Revmax HD/Towing with less then 15,000 miles. For at least the last 10,000 miles it worked great.
Changed the APPS twice with after market units, usually the highest priced ones from Geno's or other sources
Did the rewire (W-T as described on Moparman1973 site).
All ground wire connections have been polished to a bright shining clean contact.
New batteries
Since the switch I installed to force lockup works it suggests to me this is a electrical issue with the exception of the occasional downshift to 3rd gear. That has me puzzled.
I would be greatly appreciative of any and all ideas, suggestions and help. I love my truck. 24 years original owner.
I'm down to having the PCM checked. OR have mercy the main wiring harness. Please all help appreciated.

 

[garylmoore]

I understand you said it is not an AC voltage problem.
I tried everything on my truck, nothing fixed it until the alternator change. It went away and never came back.

 

[rotohead]

I'm confident it isn't a AC voltage problem but who knows.
My Nations HO alternator is about three years old. It checks out at .03 ac volts on a multimeter.
I've disconnected it and driven around and the problem is still there.
I've got a couple items I want to double check (plug integrity of the 8 pin and speed sensor and one last cleaning of all grounds before I have the PCM checked. After that I'm gonna give up and just use the lock up switch.

 

[garylmoore]

It is a very annoying problem that seems to get every 2nd gen auto owner sooner or later...
I hope you find a solution..

 

[rotohead]

It is a very annoying problem that seems yo get every owner sooner or later...
I hope you find a solution..

Yeah thanks for the good vibes. Only time I regret not being able to use a manual gearbox.

 

[Ozymandias]

Give this a shot, it may solve the Problem.

https://www.genosgarage.com/product/bd-1300030/engine-sensors-2

I installed it just to rule the APPS out once and for all.

 

[rotohead]

Found the problem. When I did the W-T rewire as written up on the Moparman1973 web site I didn't do a very good job of tightening down the new ground wire at the location next to the VP pump. It was loose enough to be erratic and cause the issue. I'm happy now and I can forget about getting a different truck.

 

[petersonj]

Good job on your part rechecking your own work. I don't know how many times I have introduced my own "problem" when I have repaired something.

Thanks for posting your fix.

- John