I am looking for any help from some folks who have a lifted 09-13 F-150 withthe two piece drive shaft. I am getting a lot of vibrations at highway speeds(55mph or higher). I have a Pro Comp 6 inch lift that was installed while I wasstationed in Alaska. I have the drive shaft spacer that goes on the drive shaftat the pinion. I also have a carrier bearing drop kit from BDS that I amcurrently experimenting with (trying to find the sweet spot). I am at a lossthough because my truck is no longer fun to drive. I drive an hour to work oneway and it blows that my truck feels as though it will rattle apart. I havetried doing all the research that I can find about this issue. Can anyoneplease help me with this issue? I feel as though I have hit a brick wall. <?xml:namespace prefix = v ns = "urn:schemas-microsoft-com:vml" /><v:shapetype id="_x0000_t75" class="inlineimg" title="Stick Out Tongue" smilieid="6" stroked="f" filled="f" path="m@4@5l@4@11@9@11@9@5xe" alt="" src="images/smilies/tongue.gif" border="0" o<img="">referrelative="t" o:spt="75" coordsize="21600,21600"> <v:stroke joinstyle="miter"> <v:formulas> <v:f eqn="if lineDrawn pixelLineWidth 0"> <v:f eqn="sum @0 1 0"> <v:f eqn="sum 0 0 @1"> <v:f eqn="prod @2 1 2"> <v:f eqn="prod @3 21600 pixelWidth"> <v:f eqn="prod @3 21600 pixelHeight"> <v:f eqn="sum @0 0 1"> <v:f eqn="prod @6 1 2"> <v:f eqn="prod @7 21600 pixelWidth"> <v:f eqn="sum @8 21600 0"> <v:f eqn="prod @7 21600 pixelHeight"> <v:f eqn="sum @10 21600 0"> </v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:formulas> <vath o:connecttype="rect" gradientshapeok="t" o:extrusionok="f"> fficeffice" /><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com</o:lock></vath></v:stroke></v:shapetype><v:shape style="width: 11.25pt; height: 16.5pt; visibility: visible; mso-wrap-style: square;" id="Picture_x0020_1" type="#_x0000_t75" alt="0" o:spid="_x0000_i1025"> <v:imagedata o:title="0" src="file:///C:\Users\CARLMO~1\AppData\Local\Temp\msohtmlclip1\ 01\clip_image001.gif"></v:imagedata></v:shape><o></o>

 

post of pic of your rear pinion angle. was the rear lifted with a new leaf pack or with blocks?

 

It sounds to me that you have a balance issue. First thing would be to get the wheels and tires rebalanced. Especially if you have oversized tires, such as 35's or larger. A lot of spin balancers have difficulty balancing the larger tires. Not to mention a lot of guys in the tire centers usually get you with in a 1/4oz. of weight and call it good. But with larger tires the minimal vibrations can and will be exaggerated causing harsher vibrations. Other than that you may need to take your truck to a driveline specialist shop to check the driveshaft balance. Is it possible that one or both of your drive shafts could have been dropped at the time of removal or reinstallation? It doesn't take much to know the drive shaft out of balance. And a driveline shop will have the equipment to check that your shafts are properly balanced.

 

The kit came with 4in blocks for the rear. I will post some pics shortly of the driveline.

 

I checked the wheels and tires first, I actually do it myself using the auto skills center on base. I use the stick on weights also. I made sure that all the wheels even my full size spare were all zeros on the computer balancer. If I can not figure out a solution my self my next step will be to see a driveline specialist.

 

This is from the drivers side.

 

Passenger side.

 

This is the top of the carrier bearing.

 

This is the carrier bearing.

 

I doesn't look like any of the U joints have been touched, at least at the carrier bearing. Any chance that a U joint is bad? A bad U joint will rattle your fillings loose.

 

tseekins, you know I didn't even think about checking those. I'm not sure how fast they normally wear out. My truck only has a little over 21k miles on it. I bought it new in 2013 but it was in Alaska, which can be a harsh state on a vehicle for sure. I'll check them to see if any of them wiggle or pop when the rear spins.

 

can you tell if its vibrating from the front or rear? could be wheel bearings too..if you ruled out wheel/tire balance.

 

The only reason I don't think that it is the wheel bearings is because I don't feel the vibration from the front. I don't feel it in the steering wheel, plus I can watch the bed shake in the side view mirrors.

 

hmm could be something to do with ujoints--they dont appear to be at a bad angle but they could just be worn out. or could be pinion gear/bearings as well. You havent noticed a brake dragging have you? the dragging can cause a vibration similar to a wheel out of balance.

 

correct me if I'm wrong here ....


but shouldn't the difference in angle across u-joint between the differential and the rear drive shaft be the same as the angle across the u-joint between the front and rear drive shafts? if they are not, then you may have found the source of the vibration.


looks to me like you need to rotate the pinion up a couple degrees. but putting a magnetic angle finder on all three locations and subtracting one from the other will tell you for sure.


in short, the angle at the pinion should match the angle of the front driveshaft.


FWIW, the 157"wb trucks with 3.73 gears are the most notorious for driveline anomalies to begin with.