Ford2WD

Multi piece drive shafts are usually balanced together as a set. They usually are timed together with a blind spline so the two mating shafts timing can't be changed. Unbolting the flange from the differential should result in no change to balance when reinstalled, reguardless of the clocking. If it did just imagine the headache on the assembly line. If your having a balance issue it's not difficult to pull out the 2 piece assembly and have it checked. Don't try to separate the two halves. I spent many years building driveshafts. It's not hard to throw a shaft out of balance. Road debris kicked up hitting one and denting it. Weights knocked off by debris or off-roading in the mud and rocks. When out of the truck simply dropping one and allowing it to be dented or knock a weight off. The list goes on. They are thin walled, about .065-.083 on most pu's, vans and cars. It's also easy to set the rear differential on stands and test for vibrations with the wheel/tire installed and the without. Yes use caution to put lug nuts on the rotors to avoid rotors coming loose during testing and any precautions needed with 4x4's. And it's just a guess but on these newer vehicles one might set a code spinning up the rears but not the fronts but still it's not guess work, it's just work and replacing multiple sets of tire without better results gets old quick.

Newfordguy29

I had a vibration from 1st almost into third, let off and it wasn't there, turns out even tho my blocks are tapered to improve the angle of the drive shaft it wasn't enough for a 2 piece, so I added shims to make her straight all the down and it was good to hook!

sw1

Glad you got it all sorted, I would have been all over the dealer IF the shake started after the gear swap. I used to be a Chrysler heavy line mechanic and i did a lot of ring and pinion swaps. It takes very little "off" to cause a whine or worse. Also you were spot on about the driveshaft, maybe you need to be a master tech. As Ford2WD stated a driveshaft can cause major vibrations with just a little weight fall off or debris on the shaft. One thing we used to do as a training exercise was to put a hose clamp on a driveshaft and put it on the lift with someone to drive the car. With it in the air have the helper put the vehicle in gear and slowly speed up the car. Man at 30-40 mph the car would shake violently!

D_Cantrell

Ok, I'm now a few days into the drive shaft rotation and it still has a slight shake at speed. The thing is it now has what feels like a harmonic vibration between 40-50mph. I really do not know how to explain it other than to say it feels like a fluttering sensation. It was there before but is worse now. Will be taking it back to the dealership this week. I will update as I find out more.

gregsf150stx

had a Silverado that vibrated like crazy. My previous F150's vibrated, but so far this '17 scab has been ok. It has 20 inch Michelins.

D_Cantrell

Ok, after a trip to Myrtle Beach, and driving around town it still has the problem. The vibration has changed though, and now comes in at a higher speed. I went back to the dealer this past Friday, and took the technician for a ride. At first he did not feel the vibration, but did hear the "fluttering" noise I did. I told him it was not that bad before the 180deg driveshaft rotation. They are going to replace the entire driveshaft assembly. I will post an update soon.

fsae150

If the driveshaft replacement doesn't work out, have them check your driveshaft angles. The angle of the driveshaft coming out of the transmission has to be equal and opposite that of the driveshaft entering the rear differential, so that the forces all cancel out. Search out a big thread on here titled "Help with FX4 Vibration" or something along those lines. Good luck.

Ifallsguy

I had a similar issue. It took a while to figure it out (checked rims, driveshaft alignment, road force/balance maybe 6 times) before we all realized BOTH rear tires were out of round. Apparently Michelin had/has issues with tires being out of round due to the way they ship tires to Ford. Ford CS us unable to get their tire warranty people to respond to my dealer. The dealer, on their own, replaced both tires at no charge.

D_Cantrell

Well, the new driveshaft was installed Tuesday, August 2nd. So far so good. The vibration is gone now, so much so the the wifey said she could tell the difference. I hope the issued does not come back, just not sure what exactly happened to the drive shaft. Its good now. Thanks for all the responses,and as always you guys are the best.

Ohsix

Google F150 Drive shaft vibration