Any GM guys who know a 700 R4 really good

82 Chevy blazer (full size)

305/700 R4

no reverse. When i put it in reverse it just makes a whirrrrrrrrr noise and does not go.

I have all foward gears.

I pulled the pan and I don't see clutch sludge or anything really off.

I don't really know what i am looking at??

Anything unusual?