transmission was shifting good then quit /wont shift in overdrive or drive

thanks

Another option http://www.ehow.com/facts_6948943_transmission-vacuum-modulator-valve_.html

Most common failure of the 700 and 4l60e is the 3-4 clutches burning up. Causes slipping in 3rd and 4th gear. Is it just free raving or holding 2nd gear? What year is the truck?

Need help does my transmission have modulator valve or selinoid stoppedgoing in thirdgear and overdrive after going through high water in a low water bridge had wires coming out tail end of tranny

does it hang in 2nd or act like neutral after 2nd gear?

yes

My 96 gmc 1500 doesn't like to shift out of first, doesn't have reverse, and won't shift into overdrive on 5he hwy. Its got fluid what could cause this \

My 89 1500 with 133K is free revving after 2nd. It is a daily driver and has had no prior transmission issues. Fluid is clean and full.