I have a 2004 gmc 6.0 4l80e. Driving down the road and something poped and didn't have drive anymore. Coasted into a gas station. Put it in park and back down in drive and there was nothing. Put it in reverse and it goes into reverse. It goes in 1st 2nd and reverse but that's it but I can manually shift it through all gears. Just want to get somebody opinion on what could be going on. Thanks in advance.

 

Maybe a bad output speed sensor in the tailshaft.

Any codes?

Are you certain you have 1st-2nd and reverse and NOT 2nd-reverse?

The latter is limp mode. Usually something electrical.

What's the history on the trans?