2000 Silverado. BANG then no reverse. Opinions wanted.

Lurked here for a minute and I've done some searching around on the reverse issues with these trucks with auto transmissions and thought I'd ask for help/opinions.

Here's what happened.

Got off the interstate, pulling away from the stop sign slowly, then BANG and it felt like the clutch was slipping. It would pull forward but it made this whirling noise, like 'ZZZZZzzzeee'. Reverse is totally gone, same noise.I was able to get it home and in my garage.

I called the local salvage yard, they have my trans with 64k miles on it w a 60 day warranty for 550.

I've seen some rebuild kits online in the 2-300 dollar range, but I'm not sure I can handle the rebuild. I've never done it before. Plenty of motor builds, mostly motorcycle stuff, but never a automatic transmission.

Thanks guys.