I’ve had a drivetrain vibration since the truck was new. 11.6 axle with 4.30 gears. Almost inaudible, but sounds like wumm wumm wumm at speeds between 68 and 75.

Peak was at 73. Most people in the truck couldn’t pick up on it, and the service manager at the local dealer said it needed the factory wheels and tires put back on (it was on the stock wheels and tires and this was 100% different from a tire vibration). I sweet talked the service writer into getting a driveshaft for it and there was no change.

anyways, ford specifies the u joint angles at the tcase and pinion should be equal, or not more than 1* different. (For a 1 piece driveshaft)

Mine measured 4.7 on the tcase, and 3.2 on the pinion.

measured a bunch of other super duties in the fleet where i work and found them to be .3-.4* different front to rear, with the largest variation being .7*.

I put in a set of 1* shims I ordered from ford and vibration is gone. 4.7* at transfer case and 4.4* on the pinion is where it ended up.

here is the ford part number: 8C3Z5A313C

 

Good for future reference. Thanks! Ed

 

Thank you for putting in the work on this. Good to know.

 

Helpful post thanks!👍👍


The shop foreman at my servicing dealership found through trial and error that 1 degree shims helped mitigate that pinion noise on my 2022 (not 100% but darn close). This is after doing a complete rear end rebuild (under warranty) that did nothing to help. $20 in parts would have resolved the issue. I suggested this but Ford has its “process”.

I have the same issue on my 24 with 7.3/4.30 gears. This only shows up when running empty or not pulling a trailer. It’s repeatable mostly above 70mph- most noticeable off throttle (coasting or throttle tip in). You can hear the ring gear cyclic noise. This is made worse by the aluminum bed which resonates that noise like a megaphone. When you add about 500lbs over the axle, noise goes away- which tells me with some weight will point the pinion angle into optimal operating range. I believe it’s set up this way from the factory to account for axle wrap under a loaded suspension for using the trucks intended purpose of towing heavy sh-t.

I need to add the shims to my 24, just been reluctant to take by the dealer to get it done cause they usually screw something else up when they work on my truck.

Maybe someone will post up a how -to with some pictures so we can diy.

 

I had a similar issue with my 2026 F350 (long bed, 1-piece driveshaft) after replacing the baby leaf pack with a beefier leaf pack. This increased the angles from carrier bearing to rear axle and gave me a vibration around 75. I slowed added carrier bearing shims at .25" and drove it until it was gone. Ended up taking about 1" of shims to correct the angle and vibration. All about those shims and spacers! Thanks for documenting your issue too!

 

Are you guys shimming between the axle housing and spring blocks or the carrier bearing or both? I know the carrier bearing was mentioned but I also read about shimming the axle housing?