Yeah confused here on just what shaft we are talking about. The front ones just have coupler and slide off as noted. Have to remove engine, trans and tunnel tin and the main drive outer tube to see any of it. Check for worn splines or cracked coupler. If it is the axle to the side, think once outer bull gear case is off, it opens the area with drive gear on it and believe it pulls out of rear also. If you were talking about the four bolts mounting the bull gear to frame, they are BOLTS with nuts on outside. You will have to remove the bull gear housing outers, keeping the bull gear and axle in it as you pull and you will see the bolt heads to frame then. You have to hold them with wrench and tighten outer nuts with another. Should be a washer and seal on the bolt heads to keep oil from leaking. Best to replace those seals or at least use silicone on them long as you have apart. NOW, if we are talking about the axles in bull gear case, you have to remove the case and bull gear as unit. Remove the snap rings and watch placement of spacers on the shaft in ftont and behind the bull gear as you slide that off the shaft. Once bull gear is removed, think might be another snap ring in cover holding the axle shaft in, not sure, then remove the axle and the hub as one piece from case. There are needle bearings and seals there. Might be good time to replace at least the seals. Getting the axle off the hub is nearly impossible, best to leave them on and work with them there. They require a big press to remove and even then sometimes never come off w/out breaking the hub. The axles can be serviced while the hubs are still on them.