Been a while. Hey folks. I have an almost 700K mile unit. Torsonial vibration around 55MPH and I can't pin it down. It smooths out at higher speeds, but I can't run 68 in a 50 and expect to keep a clean CDL. It's just a little Tupperware torpedo, but I have a lot of work into it and it's paid off and runs well. It's been aligned, tires all around run balance bead, and new torque arms on the rears. Front springs new 2021, two rear springs as well, and the front drive was re-bushed last summer. Everything is tight. The clutch, and transmission were out, rear motor mounts were replaced. $2300 worth of driveshaft work on 1&2 - new carrier bearing - the baby between the drives looks healthy. No play in pinions and wheel bearings are good. The rear air ride height is correct, so I don't think it's driveshaft angle. The only thing I haven't done is the front motor mount. Scouring the interwebs, there's only one video of a guy changing his, and what he pulled wasn't destroyed. I also don't see much about them and someone offers a high temp poly replacement, but still, if they were a problem, it would be out here. I have a vibration dampener sitting in the box and I suppose I could pull the front end off and take a swat at it and change that as well as the mount. Just seeing if I'm missing anything. Thanks in advance.
One thing to check is the phase/timing. Did the vibration exist before and after the driveshaft work? Wouldn't hurt to check the driveshaft angle to rule that out.
The shop that did the work is very good ( and also not cheap ) Yokes are in phase. They were both out of balance and corrected by rebalancing them, and the second driveshaft had a new slip spline done. All new U-joints as well. I'm wondering if I crushed or damaged the front motor mount by raising the rear of the engine to get the new rear mounts in. They seem pretty stout. I was able to bar the engine side to side to get the top bolts of the new mounts in. It could be just worn.
Hello SmoothShifter did you ever figure out the problem with the vibration on your Cascadia? My truck is doing the exact same thing as yours and i have not figured it out. Thanks
