4l80e Revs High When Shifting To 3rd

[jraymond]

I have a 2002 Yukon Denali 6.0L. I recently developed a fluid leak at the Tranny/T-Case adapter. After swapping out the adapter, I developed this problem where when the tranny shifts to third it rev high and loses almost all power. I can drive fairly normal if I manually shift to 2nd but of course I can only get speeds of 40-45 at 2500 rpm. A little more background, I did drive while I had the leak for a couple of weeks and filled as necessary. I never had an overheat and never drove it dry. I may however have driven it overfilled a couple of times. I suspect the 3-4 shift solenoid but would like to get some opinions as to what the problem could be. Any help would be much appreciated.

[govtech]

if its electrical,there is a code...

 

if the oil is/was dark,trannies done and needs a build