Driveline vibration help.

[geargrabber67]

I've got a 2019 FX4. I swapped the saggy stock leaf springs out for some OME 650lb continuous load springs and some 5100s all around. This gave me 2.5inches in the rear and 2 inches in the front. I've got the common driveline vibration when accelerating from a stop. I've checked the pinion angle as stated in the TSB, measures 5.4° when I zero the angle finder on the frame. I think the pinion angle is fine, and I've shimmed the center driveline bearing with up to 1/2" of spaces with no change. Do I need to shim the bearing even more?

Here's a pic of my driveline measurements, I've never played with a 2 piece driveline so I'm not exactly sure how it needs to be arranged to cancel vibrations. All measurements were taken with the angle finder zeroed on the transfercase output flange. Do the drivelines need to be perfectly in line with each other?

Any help figuring this out would really be appreciated! I've searched for days and almost tore the rear apart again to install some shims but I don't think that's necessary.

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[ScarzRanger21(2.0)]

Key Driveline Angle Specifications:

• Operating Angle: Keep U-joint angles under 3.5° to prevent vibrations.
• Parallelism: The transmission output shaft and rear pinion flange should be parallel (equal but opposite angles).
• Adjustment: If the angle is improper, the rear axle pinion angle can be adjusted using shims, with a TSB indicating a potential range for proper setup, though generally, you want to match the pinion to the driveshaft angle.
• Measurement: Measure angles with the vehicle at normal ride height.

It is important that the angles are equal and opposite to cancel out vibrations, particularly if the truck has been lifted, which increases these angles.

 

[Titchadesh]

From what I recall, lots of folks had success mitigating their take-off vibrations by greasing their two-piece driveshaft. Here is a thread that has additional discussion, as well as a linked video showing you how to grease it yourself if that's how you want to proceed.

https://www.ranger5g.com/forum/threads/take-off-shudder-troubleshooting.38967/

Apparently the two-piece comes from the factory already pretty dry to begin with, and grease makes a world of difference.

I myself measured my angles and I was within spec, but I still had vibrations at highway speed. Went with the Tom Woods one-piece driveshaft and it made a world of difference to how my truck drives.

 

[fusseli]

Seems like it's the 1.2 degrees at the axle if I had to guess. I would love for this to be solved and made strongly public. It blows my mind that there isn't an aftermarket kit or spacer to fix the vibration with lifts.

I had very little / no vibration with the Fox 2.0 leveling setup, but when I went to the ICON that includes the minor rear lift I get a shimmy from 10-14 mph unless my bed or hitch is loaded down. It's not not annoying. And seeing the gopro videos of what the shimmy is doing to your entire tcase/engine/transmission assembly is a little unnerving, it can't be good for longevity of the motor mounts and all the interfaces/gaskets. Let alone the output bearings.

 

[woodworker]

I would ask if the two drive shafts are phased correctly?
I’ve never had a vibration issue at all on my 2021 Ranger but the center support bearing started growling at 148,000 miles. I had Ford replace the whole driveshaft with OEM shaft and they must have gotten it right because I have no vibration even at 75 on the interstate and it is ready to turn 150k now.

 

[geargrabber67]

So far I haven't gotten any time to address it. I think I'll shim the center bearing until the two drivelines are 180 degrees out from each other and update you all. I'll also probably grease the slip yoke after that. I think the 1.2⁰ at the pinion is ok and is actually preferred to account for axle wrap on acceleration. I just don't get the purpose of a two piece driveline if they have to be perfectly lined up.

Also, drivelines are in phase. I didn't have the shimmy prior to the lift and didn't disconnect the driveline while doing it.

I don't get any vibration at highway speeds, just accelerating from a stop through 15mph.

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