The collar can sometimes be a bear to slide back. You might want to clean the outside of the torque tube up near the collar so it has no grime or grit to compete with when sliding it back. You will want to support the front end of the torque tube when disconnecting it from the transmission. I've used a bottle jack, or chain which is wrapped around both left and right frame rails, supporting the TT. I always raise the front end of the TT up til it's just touching the bottom side of the bed.
Craig
My '50 Chevy 3100 5 window, '62-235cu, 3:55 rear
My truck ....... Respect The Rust
If I'm not working on my truck, '65 m00stang or VW camper, I'm fishing with the wife or smoking Salmon.