I have been from front to back, changed wheels, tires, wheels & tires, & damn near everything. It rides like a caddy except for 66-73mph. Could rear pinion angle do this? Just a harmonic from the angle and everything spinning?

 

prob tires at that speed. take off overdrive going 60 in the auto or down shift your manual trans. when your rpm's go up the vibe should be worse if it is a rear pinion angle or front. if not get your tires balanced or check for loose suspension stuff.

 

Did you install a new driveshaft?

 

It seems, "Welcome to the club" is in order here. I have been battling the same problem for months. I have tried just about everthing: New drive shafts, rebalance new drive shafts, changing pinion angles, re-balance tires, and conplete alignment. Same issue with a harmonic between 60-65 MPH. It's more something you can hear rather than feel; like a vibration.

I recently had the 4.10 gears changed for 5.13's and now the harmonic occurs between 50-55 MPH. Happens with the trans in drive or neutral. If I remove the front DS, the sound lessons but ever so slightly.

I'm pretty well convinced that there must be an imbalance in the T-Case.

If anyone has a better idea, I welcome your input.

Tony...

 

Shifting the transmission won't change the pinion speed. Why would the drive shaft/pinion vibes get worse when the engine rpm increases?

 

Mine is a speed thing, not the tires or wheels, changed with Jeep that had no issues and mine still done it. Driveshaft also done the same way. That leaves me the pinion angle on the rear maybe. I does not care what gear, or if in gear or anything else. It definatly seems to be in the rear though. I will fart with the pinon andgle before replacing the driveshaft.

 

You still running the stock shaft? It's very forgiving on the angles, especially a 4dr. Check on the shaft and make sure you haven't thrown a weight off it or something.Also, have you pulled the front shaft to eliminate the possibility of that?

 

Maybe post a pic of your pinion angles.