I have a 2015 Ram 1500 5.7 with approx 200K miles, at highway speeds I get an intermittent bounce/vibration that comes and goes even on good roads maintaining a set speed, feels like tire or wheel, I have had them balanced by a good company but this doesn't fix the problem, I put the tires and wheels over to my 2006 ram and there is no problem, I put the tires and wheels from the 06 ram onto the problem Ram and the problem Ram's issue didn't change. I also ran without the prop shaft and CV axels installed by hammering cv joint off the axle and removing the half shafts on the front to rule them out.


Here is a list of the rest of the things I have done:

1. New sway bar links
   
2. New upper and lower control arms with ball joints
   
3. New Bilstein struts
   
4. New Bilstein rear shocks
   
5. new CV axels and stub shaft
   
6. new front prop shaft
   
7. new front and rear u-joint
   
8. had rear drive shaft balanced
9. front end alignment

 

Wheel bearing?

 

the front wheel bearings are about 6 months old and feel good, I have not replaced the rear wheel bearings, I'm not saying that they don't need replaced and maybe they are they problem, however I'm having a hard time understanding how a wheel bearing can cause a bump that feels like a balance problem and then while not changing speed or road surface the problem just disappears for awhile?

 

Yeah, I doubt that it's the rear bearings. I would still have a close look at the fronts though. I have seen bearings fail faster....... like, within a few weeks of installation......

 

so you have actually seen a wheel bearing cause a bounce?

 

Wheel bearings have some interesting failure modes, not all of which will cause noise. (which makes it obvious where it's coming from.....) Of course, it could also be something in the steering linkage getting loose....

The intermittent problems are always a lotta fun to find.....

Do you feel it more thru the steering wheel? Or the seat?

 

i feel it both places but mostly it feels like the whole truck

 

Not an intermittent engine misfire is it?? Your truck have MDS? I noticed on the shop truck, when that engaged, I could feel the vibration from the motor.....

 

no, It has MDS however, I set the cruise at 65 and it was running smooth, I waited for the bounce to occur, once the bounce occurred I put the truck in tow/haul and experienced no change, then manually down shifted to 7th gear then 6th and experienced no change at 65mph on a flat and very good road.

 

So it's gotta be something in the running gear, not the engine/trans.

Inspect EVERYTHING in the front end. Steering, suspension, etc. See if anything feels 'not-quite-right'.