Transmission will not backup and make a noise in reverse

These lights are all computer controlled ! Several modules involved DIM - dash integrated module , RIM - rear integrated module .They share information on serial data communication network . Class 2 an or GMLAN !
The rear fuse block supplies battery positive voltage through the REVERSE LAMP fuse to the coil and switch terminals of the reverse lamp relay. The DIM sends a power mode message to the RIM indicating that the ignition is in the ON position. When the driver of an automatic transmission equipped vehicle places the gear selector in the REVERSE position, the powertrain control module (PCM) sends a class 2 message to the RIM. The message indicates that the gear selector lever is in the REVERSE position. When the driver places a manual transmission equipped vehicle in reverse the reverse gear position switch mounted on the transmission closes. This provides a ground for the reverse gear position switch signal line, informing the RIM that the transmission is in reverse. For both automatic and manual transmission vehicles the RIM then grounds the control circuit of the reverse lamp relay . This energizes the reverse lamp relay, closing the switch side contacts and providing battery positive voltage to the backup lamp bulbs. The backup lamps are permanently grounded at G402. With both power and ground the backup lamp bulbs illuminate. Once the driver moves the shift lever out of the reverse position a message is send either by class 2 by the PCM or the reverse gear position switch opens causing the RIM to remove the ground from the reverse lamp relay control circuit. This opens the contacts in the relay turning OFF the backup lamps.
This is something best left to the dealer or a ASE certified repair shop . Need a factory or professional grade scan tool to diagnose an repair this . http://www.public.asu.edu/~pheanis/documents/VBI_CAN.pdf

It comes from the transmission range sensor. When you put the lever in reverse the sensor on the transmission relays this to the backup lights.

Tons of possibilities here (transmission, differential, motor mounts, transmission mounts....), so I'll ask some debug questions to help narrow it down. Does it make the noise when shifting into reverse? Also, does it make the noise only when shifting from park, or also when shifting from neutral (into drive or into reverse)? Did the noise start as an occasional, softer noise and get worse over time, or did it start suddenly? Does the vehicle lurch at the same time as the noise? What happens when you go from Reverse to Drive, or vice versa? Has any work been done recently (brakes, tires, alignment, suspension, transmission)?

no
it indicates that the torque converter clutch servo/ solenoid is not operating
could be wiring , the unit or TCM
have the fault codes read
at this point definitely not a transmission if there were no noises or problems while driving
check fluid level in the box in case you blew an oil cooler line

Sounds like the backup light switch is stuck. It is normally installed in the side of the transmission case and is activated by the transmission going into reverse. They can get gummed up over time and fail to release when coming out of reverse.

The reverse light switch is mounted on the transmission (at the front just above the oil pan) most likely has transmission fluid leaking through it and shorting out the switch -- using soap or wd40 will only solve your noise for a short time - remove belt and check your belt tensioner bearing

Does the gear selector show that is in reverse? Does the transmission have gear selector solenoids on the transmission? If so, may be a bad reverse select solenoid. Do the 'backup' lights come on when reverse is selected?

I'm not sure if you have a manual or automatic transmission. Sometimes the manual transmissions have trouble going into reverse and you need to hold it in while letting out the clutch for it to engage positively. If you have an automatic transmission, check the transmission fluid level and see if it smells burnt or abnormal.

Post a comment with a few more details and we will get back to you.

Thanks,

Tim

At left (drivers side) rear of transmission, it should be threaded in, with wires running to it.

If it drives forwards OK with no grinding noise then it is probably cable adjustment.
Unlike forward gears there is no synchronmesh on reverse therefore you need full clutch seperation. Check there is no slack in the cable at all.