Brimhall_29

Good morning guys. I'm new to this site and need some info on my xb before I venture into it....

So. It's a 2005 with 150k. Engine runs great but it has been parked on a hill at nightodt of its life with it in gear. I didn't use the ebrake a lot. The other day I got in it pushed the clutch in and started it up. Put it in reverse and nothing. No power transfer to the transmission. No grinding no sound. Almost
Like it wasn't in gear. Then i moved it to first. Same thing, let out he clutch and no power to the transmission. No griding etx. It won't hold on gear and his was one of the first time
I put me ebrake on at night lucky it didn't run down the hill.
It has a solid clutch....
So either shift linkage?
Main shaft?
What?

I'm lost any help works

Thanks ahead of time