Hey guys, new guy here but have been lurking for a while.
I need a little experienced help with my truck.
1990 F250 7.3 with ats turbo, E4od, 4x4
I bought this truck a while back with a smoked transmission, the guy replaced the converter and cracked the hub on install and then drove the truck till' all the fluid was pumped out.

I found a 94' idi trans on craigslist that had been rebuilt less than a year ago. I replaced the trans and it shifts great, problem is torque converter won't lock. Getting code 26 consistently after a drive down the highway. I replaced the FIPL as it looked like it might have been the original and calibrated it according to Ford specs.

Checked all the connections on the trans, they are in good shape.

Hooked up a manual converter lock up switch and I can hear the solenoid click with key on engine off but it will not lock while driving.

Here is what I am suspecting:
The wires on my RPM sensor are ugly and frayed.

My speedometer has a slight bounce in it, possibly a bad VSS signal?

Also, I read that the 92' and up E4od uses ABS signal for vehicle speed, is my 94' trans looking for this abs signal and only getting VSS off the transfer case output?

Thanks for the help fellers!

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I suppose a picture of the beautiful machine won't hurt