2000 chevy 1500 transmission wont reverse. While backing up driveway (slight incline) there was a bang and a surge. Pulled forward to check and whining from truck began. Truck will go in forward gears, just not reverse. Driveshaft does not turn in reverse, either. Checked trans fluid and full.

Sounds like marginally low transmission fluid. On the incline the pump and filter isn't fully covered.

https://www.google.com/search?q=1996+chevy+tahoe+transmission+fluid+level+check

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When is last time you changed trans fluid and filter?

Reverse clutches gone rear hub Asembly in back of trans also u should have no low gear or weak on probably don't take off forward like it use to

sounds like filter is stopping up, sorry but you need a transmission.

put a new in or a rebuilt

you may have broken the shifter cable somehow or it's possible the transmission is just broken internally.

Sounds to me like there is too much weight on the "park" gear. Have someone push the car forward a little bit, and do it gently, to release some of the pressure on the transmission, and it should shift from Park without a problem. I highly recommend if parking on an inclined driveway, or any hill, to use the parking brake if it is possible to do so. Good Luck

cracked drive shell. tranny needs repair, or replacement, a good shop will repair it,

check the level of the fluid first. Could be that's all it needs.

U are going to have to have the trans torn down and replace the reverse clutch drum.