Originally Posted by raycow (Post 50532)

I think you may have the transmission stuck in two gears at one time, which will lock up the entire gearset. The piece with 6 external splines and a thin ring at the front end is the 2-3 shift sleeve. GM calls it a clutch. The large gear which slides on the outside of the 2-3 sleeve is the low and reverse sliding gear.

Both parts appear to be all the way at the rear end of their travel, which puts you in 2nd and reverse at the same time. Slide the L&R gear forward so it is not touching any gears on its bottom side and see if that frees up the mainshaft. At that point you will still be in 2nd, so slide the 2-3 sleeve forward until it disengages from 2nd gear (2nd is the gear immediately to the rear of the 2-3 sleeve), which should put you in neutral.

Ray