When I got my 42 going I told my Dad about the Timken two-speed in it. He worked on many trucks with this differential and said as a rule they were pretty trouble-free. He told that the Kansas Dept. of Transportation once spec'd this rear end in a Dodge truck that had a hemi. They had one operator assigned to this truck who figured out that if he didn't like what he was doing with that truck one particular day, he would put the tranny in second gear, wind the hemi up, and sidestep the clutch. Usually he would smoke the driveshaft, but one time he got the rear end. That was the only one Dad saw broken. In this instance he said the covers that hold the ring gear carrier bearings in broke, which in turn destroyed the ring rear and pinion. The bull gears in the back were OK , though. The low gear bull gear in my truck has a chipped tooth, but has not given me any problems under some VERY big loads.
I drove a big truck for a living and am quite used to an unsynchronized tranny. I still like to use the clutch when shifting the two-speed just to be as easy on the gears as possible. My truck has a mechanical linkage connected to a shift lever inside the cab. It used to have shift cable that ran from the rear end to the rest of the linkage. The cable was very stiff and finally froze up entirely one day. I rigged up a linkage with ball joints on both ends and it works SO much better than the cable.
