You can cast with the levelwind but you are far better off to get rid of the levelwind .

The level wind reduces distance with the friction of its required gears and the pawl riding in the worm gear.
Also it help make a unholy tangle when the leader knot hits the levelwind during the cast that along with the fact you can not really get your thumb around the top of the spool with the top bar for the level wind in the way

Thing to do is to take the level wind parts off and replace the lower bar with a solid one which you can either make or import from the uk. ( Phil may also be able to make one )

Have done it myself a number of times using alloy bar .

Once you have done that put some heavy oil in the bearings make sure all the brake blocks and the brake ring is clean and enjoy casting with a real reel