[bob8619]

I've got a hopping type feeling throughout the cab between 50-53mph give or take a couple. This falls somewhere between 2100-2400 rpms. The tires are cheap but new, my mechanic says its excessive runout on two of the tires so I brought it back to Tire Kingdom but the claim they're fine. I trust my mechanic more than them but they weren't willing to replace them.



I tried two old smaller tires on the front and test drove, same issue at same speed and rpm. Then, I put those tires on the back and the issue persists at the same rpm but now at 47mph. Its always possible though that the 2 smaller tires are out of balance and its only by coincidence that the hopping is occurring at the same rpm range. But anyway because of this test I started to question the driveline . However, if I keep it in 2nd gear and get into that rpm range, it doesn't happen. Only once it gets into 3rd gear.

Since its confusing me I figured I'd just try it without tires on and the rear end jacked up, and thats when I discovered it is worse without tires than with them on. So now I don't know if its tire issue, drive shaft issue or tranny issue.