Wise men: I am baffled. And worried. I need to understand how and why I have broken two (2) axle shafts in the span of about 35 miles of city driving. I have a '46 CJ2A. My father bought it in 1969 and pretty quickly swapped in a Dauntless V6, T18 transmission and Warn overdrive. There is a little more of this Jeep's history in an "Early CJ" post about a mysterious clutch problem (solved, thanks to y'all), but it's crawled, bounced and/or dragged itself over half the dirt roads and rock piles in Northeastern California, without significant breakdowns. I think my older brother broke a passenger-side axle shaft in the mid-'70s, but that was drag racing, and I'm not really sure it wasn't the other guy (who had a V8 that supposedly could pop little wheelies) who broke the axle. The Jeep was driven only rarely in the last 25 or 30 years. I got it this spring, and I've enjoyed working on it, reliving the good old days and driving the flat pavement of Southeastern Virginia. Until, one day, I broke the rear, driver's side axle shaft. On a 25-mph road, shifting from 2nd to 3rd, as best as I can recall. I was, of course, dumbfounded. My best theory was that the axle shaft had developed a twist or a bunch of hairline cracks during some long-ago rock crawling, but had somehow hung together until it fell apart. According to this theory, I hadn't done anything wrong, I just happened to be in the driver's seat when the steel finally gave up. It took me a loooong time to replace the axle shaft. I was learning as I went, and I needed borrowed tools, helpful neighbors, time with the manual and lots of online research before we got everything apart and the broken end out of the differential, installed a new axle shaft and buttoned everything back up. Eight days later, the new axle shaft was broken, in the same place (at the end of the splines) and in the same location on Earth (same part of the same street on the way to my mom's house. Weird.) Some fun facts that may or may not help with the diagnosis: -- This time, I starting from a stop. In 2nd gear, as usual. I'd say I was making a "spirited" start, but not trying to burn rubber or anything. I absolutely did not redline it and pop the clutch. -- We'd had to remove the carrier from the differential to get to the broken piece (This is a Dana 41 rear axle, not the full-floating kind.). Scary as that was, it came out and went back in without much trouble. -- The first replacement axle shaft I got was too fat at the tapered end. I could not get the hub all the way on. The diameter at the very end measured .018 inches wider than the original. I eventually had to give up and get another shaft. -- The second replacement shaft was the opposite -- thinner at the tapered end. I wish we had measured it, too (I still can, but the neighbor with the tool is out of town), but the difference was significant. The hub went on very easily. Even the bearings went on easily. Probably too easily. -- As a result of this smaller-diameter taper, the hub ended up seating slightly farther along the axle shaft, compared to the original. As a result, the brake drum rubbed the backing plate, ever so slightly, sometimes. -- I had a heck of a time getting the freeplay right, but after much subtracting and adding of shims, I do believe I got there. -- This transmission allows you can put the Jeep in in low-range 2WD. Dunno if that could be a factor. Maybe that's a little too much torque in one place? But that's no way to drive around town, and I certainly wasn't in low-range at the time of either break. So: -- What the heck? You break axle shafts by drag racing or pinching your wheels between rocks, on a steep hill, putting it in granny gear, revving the engine and being mean to the clutch right? Not tooling around town, right? -- Could I have done something during reassembly that contributed to the second break? What? If I shimmed improperly, the damage would be to the bearings, not to the axle shaft, right? -- I'm ordering my third new axle shaft. Ugh! I guess I'll pay more and get New Old Stock this time, on the theory that it will be more likely to be within tolerances (I understand that "within tolerance" is a range, that both "Fatty" and "Skinny" may actually be within tolerances, and that my hub hole my have a smaller-than-usual diameter, still "within tolerance," but making a bad match with "Fatty." -- Surely I don't have to drive my Jeep, a vehicle world-famous for toughness, in constant fear of snapping axles in two? Any wisdom to offer? Thanks in advance.