Howdy Appraiser!
Definately check to see if all the wiring is out of the way ( check to see if you have given the barrel recoil-elevation mechanism too much slack, it may be binding on turret rotation. Make sure you feed them through the round hole in the metal turret brace). I would also check to see if there is any loose debris in the gear "Teeth" themselves.
You can also use a plastic safe grease (if you have some of the supplied white grease left over from the gears) Don't use petroleum jelly, it will soften the plastic.
When you replace the turret on the hull, make sure it's pushed all the way down, before turning it toward the front. You will here the clicking sound, of the gears, if done properly.
When I was finished with my tiger, I made sure that all the wires stayed in place, with a lot of zip ties.
Let us know if you get it fixed!