Measured rear driveline angles

polarys425 · June 5, 2016

Ok, revisiting this. Last night I had the time to pull the truck into the garage and measure the drive line angles. Driveshaft was angled 5*. Rear pinion was up around 4*, so a 1* operating angle. Tcase was down around 3 or 4*, making a 1-2* operating angle. They are fine.... These are very small operating angles. I must of goofed up measuring my angles on the driveway originally. Sorry guys... no dice here. angles are fine.

Not so fast. I'm wondering if maybe angles are changing with temperature, or if something is shifting around. I've also noticed that there have been times where I didn't notice any vibration at interstate speed 75ish, but after getting off the interstate, and getting back on with a full throttle acceleration, I felt some vibration at that 75 mark.

FL335i · June 5, 2016

you and me both man.... Something could be making the pinion angles change.

gone_fishing · June 6, 2016

I don't know much about drivetrain angles except what I have read in this thread. Would a appreciable amount of weight in the bed change these angles? If so this could be a way to test if changing the angle reduces vibrations.

Zachlovesfood · June 6, 2016

The axle is probably floating and moving around, i.e. axle wrap due to under torqued u-bolts. If they're loose, then temperature would definitely cause changes. I torqued mine down around 100 ft. lbs. and as a result, over the course of a few days, I'm guessing the axle settled and I never felt any sort of vibration again.

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Jeff5347 · June 6, 2016

I had been curious about the angles as well as I get a vib/hum at 70ish. Now before I added my 2 inch rear blocks I don't remember if I did or didn't have a vib. Once I added my 2 inch block that is tapered I def noticed it. On the street there's no problem but hit the highway and it is real annoying. My initial thought is the taper of the block is the problem. After seeing angles you guys posted like the 7° up tilt of the pinion mine now has maybe a 10° which I'm assuming is way out of whack. My other assumption is getting a flat block would bring me back to the factory angles and stop or at least reduce my highway vib. Thoughts?

Oh as far as I know the block has a 3° taper

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FL335i · July 4, 2016

Jeff-

your blocks should not have any taper. Let's assume your u-joint angle were correct prior to installing your lift. If that is the case, the blocks should be flat. That would keep both rear and front u-joint angles the same, but with the block they would be larger operating angles.

Zach-

My u-bolts were very under-torqued. I torqued them down to the spec'd 59#. However I never did the yield of 130 degrees after the 59#. They must of been around 30-40# prior to me torquing them.