2001 Cherokee Sport Shaking after bumps

[schultmb]

Wondering if anyone can help me out....when going about 65-70 MPH or faster after I hit fairly substantial bumps, the car shakes uncontrolably until I pull over and slow the car down to about 10-15 MPH. Wondering if anyone has heard of this problem. Someone joked it was known as the death rattle. Any advice would be greatly appreciated.

[Bounty__Hunter]

I called it Death Wobble (DW) and I wasn't joking.

It's common, most often happens to coil spring suspensions after a lift. I had asked you in the other forum what year jeep you have and what mods you have made. That will help us help you.

There are many causes to DW and we'll help you narrow it down. Be specific if you have a lift, list each part you changed out.

[schultmb]

I posted a response in the other forum...I bought the car used about two months ago, so I'm not aware of the modifications done. I can tell you the first time I brought the Jeep in to get this problem fixed they found a modified steering damperer, which they exchanged with a stock one. I am not aware of the other modifications. Right now they are not sure what the problem is. Unfortunately, I do not know what previous modifications were done. I am slowly learning I suppose. They are having trouble recreating the problem (which makes me laugh). So, I'm not sure where to go from here. Thanks for any help you can provide.

[Bounty__Hunter]

If it's stock then it's either out of alignement or something is worn out. Make sure a quality shop does the alignment and the caster is set to stock spec.
Depending on mileage and how hard the previous owner was on the jeep, you may have a worn part. First things to check are the track bar and control arms (4). The track bar needs to be very tight, on both ends. The upper track bar mount should be very tight against the subframe. Probably have to remove the control arms (best done 1 at a time) to inspect the control arm bushings.

If all that checks out, it's on to the steering. The damper is a bandaid fix that can hide problems, the stock one sould be fine with stock size tires. Check for worn tierod ends, they're fairly inexpensive and should be replaced if you have high mileage.

Last I'd consider a heavier draglink and tierod. It's easy to flex the stock pieces by hand, and they flex when driving as well. This flex could lead to or aggravate this death wobble.

How many miles on this jeep?

	Track bar A track bar is a component of a car suspension system that provides lateral location of the axle. While the purpose of the rear suspension of an automobile is to allow the wheels to move vertically with respect to the body, it is undesirable to allow them to move forward and backwards, or from side to side. It is this latter movement that the track bar is designed to prevent. It is a simple device, consisting of a rigid bar running sideways in the same plane as the rear axle, connecting one end of the axle to the car body or chassis on the opposite side of the vehicle. The bar is attached on either end with pivots that permit it to swivel upwards and downwards only, so that the axle is, in turn, allowed to move in the vertical plane only.

	Caster Caster angle is the angular displacement from the vertical axis of the suspension of a steered wheel, measured in the longitudinal direction. It is the angle between the pivot line (in a car - an imaginary line that runs through the center of the upper ball joint to the center of the lower ball joint) and vertical.

[schultmb]

approx. 38,000 miles. I took it to a "respected" jeep dealership. Still waiting on what they tell me. I appreciate your advice. They wanted to take it out on a road test to recreate the problem. I hope the previosu owner did not alter the stock parts too much because those aren't covered under my warranty.