so after having my rear end rebuilt i noticed a vibration under acceleration at anything above 50mph. cruising is fine and so is decel. went and got tires balanced and still there. after some searching i learned about driveshaft angles and what not. so i just took the measurements just now and came back with the driveshaft at 11 degrees, the t-case yoke at 0 and the pinion yoke at 5. so then i have to subtract the t-case angle from the driveshaft angle (11-0=11) and then i take the differential angle from the driveshaft angle (11-5=6) giving me and operating angle of the first u-joint of 11 degrees and 6 degrees for the second, correct? and hi guys, i live in socal and recently bought this truck fixing one thing at a time
If you don't have a cv joint you're axle flange and tcase flange need to be parallel to eachother. If they're not they'll cause what you're talking about. If you have a cv joint then you can point the axle flange directly at the tcase.
ok, so i need to pull the rear diff down to make it parallel. i read something about shims? or others add spacers to motor mounts to level things out. it seems like loosening the shackles and just doing a little rotating it could get things to match better? unless im missing something obvious. thanks for the quick help
there was a vibration but it was barely noticable since i live on base i never take it out in town til yesterday where i actually got on the highway. i took it to a trans shop where the rebuilt the differential. i think he said the carrier bearing was basically destroyed. i was getting a nasty CLUNK from the rear end, not the typical GM clunk. i replaced the u joints prior to the rebuild. caps are fine, clips are on the back. the drive shaft didnt look damaged when i pulled it to replace u joints. a thought occurred to me that there is no master spline on the driveshaft yoke. i put it in correctly and they may not have. but it looks like it has weights on the shaft so i figured maybe its 0 balanced. in the end the rear diff and front prop shaft were rebuilt.
Your pinion looks to be pointed at your t-case. Get some shims and turn it down to where it matches the output of your t-case.
You should have heard mine when it looked like that. I was young and dumb and didn't know better.
Throw some shims in there or add a cv joint and I bet it'll get rid of the noise. The only way you'll change it with the shackle is by using a longer or shorter shackle.
Pull the drive shaft and put the angle finder on the face of the yoke before you do anything. The areas you put the angle finder on in the pics is not machine flat and is prob not true with the center line of the input/outputs.
ya they arent the best spots, but on the side there is a flat spot from where the finder was hanging. i kept trying to get the u joint carrier parallel to the ground and kept missing by that much. ill prob just take it back to my trans shop and see how much for a shim job
Yep. Pick up a set anywhere from 5-7 degrees and you should be set.
DIY4X is who I suggest but there are others. Just make sure they are not AL or cast.
so to bring this thread back from the dead, i still have this STUPID vibration. got real tires balanced, fixed the pinion angle by flipping the blocks (they were reversed by prior owner). vibration seems load dependent. at ~60 mph you can start to feel it, but when i accelerate you can really notice it. ive seen some people say out of round tire, but im hoping that wouldve been caught by the tire balance. and i would also think that kinda of vibration would be constant regardless of throttle input. i dont feel a shimmy in the steering wheel.
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