4l60e slipping? or TC locking and unlocking

[blindawg]

I swapped a 5.3 into my 2001 blazer and am using the factory 4.3 transmission. I used the 4.3 harness and just repined the connectors and added the coil and injector wires. I'm having a problem with the transmission feeling like its locking and unlocking the TC, or its slipping really bad at random times. When I try to go WOT it shifts out of a gear, sending it to the rev limiter, but never shifts into the next gear. At partial throttle it will do the same thing but its not close enough to the rev limiter to reach it before either I let off, or it catches itself. This is the second transmission this is happening with and it came with a bad transmission, so I'm trying to figure out what it could be. Here is the tune and a couple logs I took. I'm not sure what to look for, any help is much appreciated as always. Thanks in advance!
Branden

17853
17854
17855

[joecar]

Log the pid TCMODE to see if TCC is being commanded locked or unlocked.

If it "shifts" out of gear then that is a mechanical failure (internal clutch is slipping as engine load exceeds its available/degraded capacity)...

log the pid TRQENG to make sure that the PCM is calculating sufficient engine torque (if it is too low, then the VE/MAF air model is calculating too low).

If this is happening to multiple transmissions, check wiring and grounds for intermittent opens.