Call your local GM dealer (or go online) and check for recalls or campains on your vehicle cocerning this problem.
If the SHIFTER will not go to the reverse position check for an obstruction in the shifter linkage from where the steering shaft exits the cab down along the firewall to the frame where there is some type of bell crank that changes the back and forth movement of the shifter linkage to rotation force connected to the side of the transmission; if there's no reason for the linkage to be bining your next stop is at a reputable tranny shop. Call the BBB and ask.
pretty vague, could be worn linkage in your gear box that pushes the switch.
i don't know when this question was posted but to answer your question more than likely your planetary gear is messed up. The planetary gear is that part of the transmission that take the single direction "clockwise" movement of the engine and convert it to "counter clockwise" motion
Your gear linkage is offset!! Or you are on a steep down hill
It is simply indicating that it is in gear.
You need to lift the collar on the gear stick to engage reverse gear
check your cross member on the gear selector it sometimes pops off
Reverse gear
Quite possibly a worn second gear clutch pack.
a bad driver?? Seriously, i could be the ECU
Low fluid, shifter malfunction, electrical malfunction, internal mechanical malfunction.
reverse
no but you can by a kit on eBay for a reverse gear