Bell A30D

How big a job is it to change the pinion shaft seal on the rear axle?...is it as simple as it seems?.....pull off the drive shaft, pry out the seal and then drive a new one in?

Any clues where the fuse for the cab HVAC system lives?.....its not in the roof with the rest of the fuses

Is there a way to stop the trans upshifting to 3rd when going down a steep hill is there a 'trans hold' switch or do I just drop the lever back in to 2nd?

Bell A30D