18 speed. Shifter has a lot of play while in gear (slop)

Give the top of the transmission a good wash before you unbolt the tower. Or at least blow it off with a blow gun. You want to keep as much of that dirt out of the transmission as possible. I'd even go as far as putting a piece of clean cardboard over the opening while the tower is out. Also watch the 3 detent springs, they sometimes can stick to the tower when you pull it. Don't want to drop those inside.

 

Thanks for all your help