Oscillating vibration between 50-55mph?

[Hook]

I have had this oscillation since I bought the Jeep used. It is a stock 05 Unlimited.

The interval between oscillations is a little less than one second. It is pretty significant; actually adds some vibration to the ride. Disappears after 55. ALSO DISAPPEARS IF I DOWNSHIFT BY TURNING THE O/D OFF when it is occurring. Does not occur at the same rpm range in other gears.

Automatic transmission model. Stock as stock can be.

Any initial ideas, guys?

 

[SteelHeadz]

Possible Torque converter shudder.

 

[ljrubitm]

Could be a number of things .
bad u-joints
water in the tires using the gas stations air
needs an alingment
worn out bushings
you could be missing a weight off the tire
worn out shock

 

[Hook]

Could be a number of things .
bad u-joints
water in the tires using the gas stations air
needs an alingment
worn out bushings
you could be missing a weight off the tire
worn out shock

-Just remembered that the shocks are the one thing that is NOT stock. I replaced them with conventional Bilsteins.

-I cant see how water in the tires would disappear when I downshift. Wheels are turning at the same speed.

-which bushings?

Thank you for those other suggestions. I will begin to look at those possibilities.

I have also noticed a slight shaking in the steering wheel at lower speeds. Kinda assumed that maybe the steering stabilizer was going south. I testdrove an 05 Rubicon off a dealer's lot and as I was coming off the freeway offramp, the steering wheel began shaking VERY violently for about 3-4 seconds. Never stopped till I used the brakes to slow it way dow. This, and my slight shaking, led me to believe that steering stabilizers may be an issue with these models. Is it/

I;m welcome to any and all suggestions.

 

[SteelHeadz]

-Just remembered that the shocks are the one thing that is NOT stock. I replaced them with conventional Bilsteins.

-I cant see how water in the tires would disappear when I downshift. Wheels are turning at the same speed.

-which bushings?

Thank you for those other suggestions. I will begin to look at those possibilities.

I have also noticed a slight shaking in the steering wheel at lower speeds. Kinda assumed that maybe the steering stabilizer was going south. I testdrove an 05 Rubicon off a dealer's lot and as I was coming off the freeway offramp, the steering wheel began shaking VERY violently for about 3-4 seconds. Never stopped till I used the brakes to slow it way dow. This, and my slight shaking, led me to believe that steering stabilizers may be an issue with these models. Is it/

I;m welcome to any and all suggestions.

Check the upper shock mount and make sure that the stud is centered in the bushing and mount.. Go to the Search bar and type in "Death Wobble" . There has been a lot covered regarding this subject.