well - get it off - you know how to do that now

to take a gb apart you need a pair of needle nose pliers and a few sized socket pieces + extensions + compatible ratchets. Time consuming.

Also you should really replace the ISB , diff bearing/s , countershaft bearing + seals etc.For a first timer with a bit of knowledge and all the right tools about 4-8 hours with the GB. + time for the gb removal / install