What is going on with my tranny?

Heres what Ive got:
92, Chevy, 2500, 4x4, 350 motor, 4L80E auto

recently it seems that the transmission shifts way too early and at low rpms.
I will mainly see this when i go to put my foot on the gas when going up a hill and it will shift right away to the higher gear causing the engine to bog down giving me no power to get up the hill. If i punch it to the floor it will down shift and all is good. this gears i see this in is from 2 to 3 and all the rest after that. this does not only happen going up a hill but it is the worst at that time. Any Ideas??

Check for transmission and engine codes.
post back any codes.
MT

Check for transmission and engine codes.
post back any codes.
MT

MT: Can you get tranny codes from a '92 OBD1 system? If so, then I've learned something today (and that's a good thing at my age)

Not real sure about the '92 (as the above post will show) but if you have a TV cable attached to the throttle body linkage you may want to check that for proper adjustment to the tranny.

MT: Can you get tranny codes from a '92 OBD1 system? If so, then I've learned something today (and that's a good thing at my age)

Yes on 1992 if a 4L80E transmission.
The 4L80 E is all electronic no TV cables or modulator valves.
MT