Delayed Engagement?
 

im pretty sure I have Delayed Engagement. I put it in gear and it takes a couple of seconds to engage.
also when reversing it tends to be a lil more hesitant to go backwards, when it does go backwards it can sometimes make a bit of noise. It goes forward and accelerates just fine.

Check the fluid level and condition. The backing up and noise may be the issue as that is a common complaint when the rear planetary gears are failing. How many miles on the vehicle?

its got like 200k+ and was parked for like 6 months over the winter.
I checked fluids and topped oil up before attempting to fire it up. ran a lil rough at first but seems to run like it did before it was parked.

Do you have rust on the brake rotors? Rust in the rear drums?

Yes the obvious rust on the rotors. Probably on the drums. It rolled backwards downhill no problem. After having the ebrake on for the 6 months it was parked.

I would look at other areas before heading in the direction of transmission. Good luck