i have a 2003 gmc 1500hd that wont shift into overdrive anyone have similar problems? i need to replace my bank 2 sensor 2 o2 sensor so i have a check engine light on, could that be throwing the truck into limp/home mode so it wont shift into top gear?

 

check codes first. Once all are checked and fixed you can then go on to trouble shoot the trans. Misfire codes will not allow the Torque converter to lock which could be mistakine for no OD. you sure no OD?

 

ya you were right threw in the new 02 sensor (bank 2 sensor 2) and bam had top gear back and yes i agree it was the TC not locking up