I just got my fresh 80e together and wanted to confirm the pressures. The dipstick was calibrated as well, so fluid level is proper. And the pressure is controlled via epc.

At hot idle in park it makes 75psi steady. Same pressure in gear. The pressure in reverse jumps to around 200 with light throttle. LIghtly leaving from a stop it jumps to 150-160psi and drops down to about 80-90 light cruise. Once lockup comes on, it immediately jumps to 100psi, and goes up based on load.

I haven’t done WOT yet, but at about half throttle it goes up to 150-160 and tapers off when load decreases.

What is the proper procedure to test? I am assuming the EPC adjusts the pressure based on engine load? To note, the trans seems happy. It shifts good and generally feels like it’s working properly.

 

All you have stated looks normal. Pressure at various throttle and load will vary vehicle to vehicle . But looks to be in normal ranges .

 

The pressure curve is more like this.



Engine torque is is built on the low end. Torque is what will slip a clutch pack more than HP. So the pressure curve goes high at first and usually cut's back a bit with MPH. The PCM's are calculated that way.
Throttle will drive the pressures high too. Don't be surprised if you see 300psi in reverse at heavy throttle.
Here's a pressure guide from an early 4L80 GM hand book
Gear Range -------------------------Line Pressure Range
Drive, Park or Neutral ----------------35 - 171 PSI
Reverse ----------------------------------67 - 324 PSI