Hi folks,
I'm new to diesel-place and new to diagnosing electronically controlled trannies.

I have to diagnose a 4L80E in a '96 C2500 6,5l diesel truck.
I do not have a tech1 as recommended in the repairbooks.
So I bought a OBD2 laptop adapter to communicate with the TCM.
I can read real time data from the engine rpm, load etc.
But no way getting something transmission related.
I don't even see a TCM to choose.
What software should I use.
Is there another way to do the line pressure test?
What I'm doing wrong?

I'm running out on ideas now.
Please help.
Many thanks
Rosi

Line pressure is best done with a pressure gage installed to the pressure tap. That is located just above the shift lever on the transmission.
The pressure should rise with throttle. I can look up specs sat and post if needed.

I don't exactly know about line pressure being measured at the pressure port on the left side of the transmission. There is only one port to check though. reverse is the highest pressure reading and that shoud be around 300 310 max. The forward gears should read roughly around 90 130 or so from the top of my head. These readings should be governed pressure readings with the exception of reverse which might be line pressure.I should look it up later if I get the chance..