Hey guys, I've been fighting a driveshaft vibration for quite some time now. Been reading a lot on forums and cannot find a solution. I would really appreciate some help. Truck: 01 Tacoma 5-speed RWD (2.4l engine) (Single piece driveshaft) (Completely stock truck - 230k miles) Problem: Shuddering during acceleration. It has become so violent to the point I can no longer drive it. It does not happen in first gear (may be irrelevant), usually in 2 gear and higher. I put truck on jack stands and had someone drive it. There is a clear shuddering sound heard through drive line. What I've done so far: I replaced both ujoints. This changed the characteristics of the shuddering (i.e. what RPM it begins, speed, etc.), but ultimately it is shuddering just the same and is only getting worse with each test drive. I checked the engine mounts and they look solid. Tried shaking engine, no movement whatsoever. It is on tight. Check Transmission mount. Also appears solid. Removed driveshaft and checked diff flange bearing. No movement in or out. Rotates slightly, but sounds like I'm moving gears in the diff a little, feels normal. I read around that pinion angle may cause this issue, mainly on lifted trucks but also can happen from weak leaf springs. I did a lot of measurements so I will do my best to explain. Transmission: 87.8 (pointing to ground - from 90 deg) Driveshaft: 5.3-5.7 Rear Diff: 88.1-88.3 (pointing up - from 90 deg) This would make the difference between Transmission and Rear diff .3 - .5 degrees. The joint angle at the rear diff to driveshaft is 93.4 - 94 degrees. Does this look correct? I am a bit confused if the difference between the Trans and Rear diff needs to be as close to zero as possible, or if the rear joint angle needs to be as close to 90 degrees as possible.