1995 Chevy Suburban It won't shift into reverse& won't

A couple questions:
Do all the forward gears seem to work ok?
What gear were you in when you heard the "bang", low, 2nd, 3rd, etc?
Does the trans even attempt to backup?
If you pull the transmission pan we will be able to tell a lot by what's laying in the pan. All in all, it doesn't sound good.

1. The forward gears all seem to work. But it would not go over 20mph in any forward gear.
2. When I heard the bang, I was in Drive. I was not in 3, 2, or 1st. I was probably going about 15-20mph.
3. I will not attempt to go into reverse at all.
4. I pulled the pan and the fluid is good. I did see a small amount of shavings, though.

Does it seem like the trans is staying low gear, won't shift into 2nd or 3rd? A small amount of "small" shavings is not uncommon with a trans almost 200K on it. Reverse gear uses the low clutch plus a reverse planet gear to back up. If the "bang" you heard was the reverse planet breaking, you have major transmission problems. The reverse planet gear is the last part to come out of the trans case when disassembled.

Thank you for all of your time and assistance with this issue. I do appreciate it. Now I know exactly what I need to have done. THANKS AGAIN!

Glad to help. Anything else, you know where to find us.