[nvrdone]

OK, what kind of trans - 3 spd, 4 spd, etc?
ON my m21 4 speed its real easy
If you have shift arms that bolt on the trans, install all of them. Then jack up the rear wheels. On my 4 speed I can move each arm 3 clicks. 1 forward,1 nutral & 1 back. Do this on the front 2 arms. the rear arm is just reverse - 1 click each way. Each time you move an arm, see if the drive shaft turns.
I know this is probably as clear as mud, put play with it. you will get it to work