Been working some driveline vibration issues for about a year. These were as a result of my Icon Stage 4 and Dakar lift. Long story short, I've tried everything. Carrier bearing drop, new carrier bearing, spacers with the new CB, axle shims and last but CERTAINLY not least; a single piece drive drive shaft from Tom Woods. The single piece shaft (with a double cardan input joint) solved the issues for me. I was very pleased. However, this week I regeared to 4.56 gears and now the shaft is expected to spin a LOT faster to achieve a desired speed. And with that, I'm hitting the critical speed limitations of the shaft and it vibrates like hell over 50mph. I removed it and put my original two piece shaft back on and I have take off vibrations but the high speed vibrations are gone. So now I'm back to square 1....I have to figure something out. The single piece steel shaft is too long and won't spin fast enough without acting like a jump rope. The two piece shaft introduces violent vibrations while starting off quickly from a stop. Questions Does anyone make a single piece shaft (maybe aluminum) that can spin faster but is still ok for offroading shenanigans? Is it possible to weld on double cardan input joint to the stock two piece drive shaft? My gut feel is this will fix the take off vibrations.