I am trying to pin down a vibration that I get at 50-80 MPH on my 2007 Ram QC Thunder Road 5.7, which has 50K miles and which I recently purchased. I feel the vibration primarily in the seat and the empty passenger seat visibly vibrates. There is very little vibration coming through the steering wheel, so I assume my problem is related to the rear wheels or axles.

As soon as I purchased this truck I had new Cooper Discover HT Plus tires mounted on the OEM 20"x9" Chrome Clad wheels and they have been balanced on a Hunter Road Force balancer. The Hunter balancer reported that both rear wheels/tires were borderline failures, but they did balance. To ascertain if a defective tire was the cause, my tire guy replaced one of the new rear tires, but that did not change anything.

I jacked the truck up and had my wife put it into gear and neither rim appears to be warped or bent, at least not to the eye.

The shocks could be worn, but the truck does not bounce like a vehicle usually does when the shocks are worn out.

While I had the truck jacked up, I placed a long bar under each rear wheel and applied upward motion (like you do when you are checking front ball joints). Both rear wheels will move vertically a little bit, I am guessing about 1/16 of an inch. There is only a very small amount of horizontal play, which, I am told, is normal.

My questions: How much vertical play should there be in the rear axle bearings? Could this cause vibration similar to an unbalanced wheel?

What other issues could cause this vibration? Thanks for your help!!

UPDATE: I went today and had the tire guy put another new tire on the other rear wheel (they had already replaced one of the new tires) and that took care of much of the vibration, so far at least.... The tire guy said something about the cord separating.... That means that of the four new Cooper Discovery HT Plus tires that I purchased, two failed withing just a few hundred miles (unless they were defective when mounted...)

Anyway, I still would like to know how much vertical play is allowed for the rear axle bearings.... Thanks for any help on that!!!

 

Anybody know the answer concerning the accepted vertical bearing play??

Thanks!!

 

I have looked the web and in my service manual for rear axle bearing play tolerances this 2007 Ram 1500 QC trying to find out how much vertical play is acceptable, but I cannot find anything definitive....

A couple of guys on other forums said that they thought that some play was normal, then another said that 1/16" is way too much play....surely there is some tolerance spec on this issue....does anyone know??

I just want to stay ahead of the possibility of a bearing throwing metal into my Differential....I had a Ford where the bearing shed enough metal to ruin my Diff before the "tell-tell noise" began....cost me a bundle....any help would certainly be appreciated!!

I just do not remember any previous car or truck having any vertical play in the rear axle bearings....

 

My ram has a vibration also. I jacked the rear end up today and mine has about a 16 th of play in it holding the tire at 12&6 I don't know if it is suppose to be there or not hope we find out soon its driven me crazy.

 

Coalminer, I finally took my Ram into the shop to an older, experienced guy that had rebuilt a differential on an Explorer that I had...he is supposed to be good....I had him change the dope and check the bearings. He told me that the play that I have is proper and normal. I have just never noticed any play at all in other trucks...thus my concern. Anyway, maybe it is normal.

If you find out otherwise, let us know!! Thanks!