2002 gmc Sierra 4.8 liter trans help!!!!!!&#33

[Georgebaumann]

So the other day I took my truck a off roading in local pit and when I tried to leave my trans wouldn't shift out of first til about 4000 rpm and when I go to pin it hits the rev limiter like it's slipping. But every other gear shifts fine and I still got power. Any help on what it could be is appreciated. I hope I don't need a new trans

[oldschool327]

Sticky 1-2 shift solenoid

 

Any codes

[Georgebaumann]

i check when i get off in the morning

[gmtech4]

if no codes and oil is dark ,rebuild time or replacement and cooler flush either way