How to fix the worm gear on a Bell&Howell 1695 TQ11?

Looks tricky, need to remove the shaft the gear is on and the carier. Not sure if the drive wheel end needs removing too, I cant see a simple way of doing it without really upsetting frame setter etc. I think there are two screws at the back of the righthand carier that might loosen things, otherwise its strip and withdral driveshaft to the right.

rothko1@excite.com
September 2007