Level of difficulty changing 8 3/4 gearing

changing the oil and changing an engine are both pretty easy with basic tools. Changing the gear ratio will require some indicators for measuring side play, backlash, etc and most likely a hydraulic press. It is not real hard but does require some knowledge to get it right. I would see if there is a member close to you that can help you set up the gears in the 3rd member once you get it out. I have done a number of them especially when we were jeeping a lot but am in no stretch of the imagination an expert. If you set them wrong, they will not wear properly and will be noisy or worse.