My TC is locking and unlocking back and forth with the cruise control on just going 60 down the highway.. Does that sound like an issue related to the TPS?
Dave (from Goerend bros.) said he'd replace it.. its most likely a TPS issue.

Also, when doing a 4WD launch, it doesn't want to shift to overdrive until 4K RPM, and it will only shift if I let out of it.

 

sounds like a tps, take yours off and clean it, put it back on, if it doesn't help than just change it out.

 

https://www.dieseltruckresource.com/...light=pappyman In pappymans gallery you can see photos of one apart. They will clean up and work, I have taken them apart and cleaned and relube with dielectric grease and they work great, also read about taking or rewiring the tps to the pcm and adjusting the voltage. Goodluck,,, Rick