This is a 2000 Jeep Grand Cherokee, 130,000 miles.
The sympton is just a bit hard to describe. When I am driving on a rocky, gravel road, I feel a shaking in my steering column. It is very weird....... if the road is very rutty, I can only assume that something in the front end is worn and loose, and this sets up a shimmy that I actually feel quite strongly in my steering column and steering wheel. It seems that I can actually "hear" rattling in my steering column.
This is NOT death wobble. I have no such symptons at any speed, on a smooth or even semi smooth road. It is only there when I travel up and down our very rutty gravel mountain road, and I feel it even at very slow speeds.
The "jerking" steering column is quite pronounced.
I am thinking of tie rod ends............ or steering stabilizer , or ball joints ??
What is the most likely culprit?
BONUS QUESTION-- not related to above primary question..... I have a low frequency, rumble type rattle underneath my car. It sounds like it comes from the center of the car, toward the back 1/2 of the car. Of course, I can't be sure. It sounded so much to me like part of the exhaust system, I had my mechanic put in on the rack and check all of that very carefully. He could find nothing loose. I only hear this when I am going over rough roads, with many bumps etc. It is not a high pitch rattle... it is more like a rumble.
What other parts could I suspect, and inspect to locate this noise. Could a defective wheel bearing exhibit this noise? How does one check the status of a wheel bearing ?
Vehicle vibration can be caused by: ² Tire/wheel unbalance or excessive runout ² Defective tires with extreme tread wear ² Nylon overlay flat spots (performance tires only) ² Incorrect wheel bearing adjustment (if applicable) ² Loose or worn suspension/steering components ² Certain tire tread patterns ² Incorrect drive shaft angles or excessive drive shaft/yoke runout ² Defective or worn U-joints ² Excessive brake rotor or drum runout ² Loose engine or transmission supports/mounts ² And by engine operated accessories Refer to the appropriate Groups in this manual for additional information.
VIBRATION TYPES There are two types of vehicle vibration: ² Mechanical ² Audible. Mechanical vehicle vibration can be felt through the seats, floor pan and/or steering wheel. Audible vehicle vibration is heard above normal background noise. The sound can be a droning or drumming noise. Vibrations are sensitive to change in engine torque, vehicle speed or engine speed.
ENGINE TORQUE SENSITIVE VIBRATION This vibration can be increased or decreased by: ² Accelerating ² Decelerating ² Coasting ² Maintaining a constant vehicle speed
VEHICLE SPEED SENSITIVE VIBRATION This vibration condition always occurs at the same vehicle speed regardless of engine torque or engine speed.
ENGINE SPEED (RPM) SENSITIVE VIBRATION This vibration occurs at varying engine speeds. It can be isolated by increasing or decreasing the engine speed with the transmission in NEUTRAL position.
VIBRATION DIAGNOSIS A vibration diagnosis should always begin with a
10 mile (16 km) trip (to warm the vehicle and tires). Then a road test to identify the vibration. Corrective action should not be attempted until the vibration type has been identified via a road test. During the road test, drive the vehicle on a smooth surface. If vibration exists, note and record the following information: ² Identify the vehicle speed range when the vibration occurs ² Identify the type of vibration ² Identify the vibration sensitivity ² Determine if the vibration is affected by changes in vehicle speed, engine speed and engine torque. When the vibration has been identified, refer to the Vibration Diagnosis chart for causes. (see below)Consider correcting only those causes coded in the chart that are related to the vibration condition. Refer to the following cause codes and descriptions for explanations when referring to the chart.
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TRR-Tire and Wheel Radial Runout: Vehicle speed sensitive, mechanical vibration. The runout will not cause vibration below 20 mph (32 km/h). WH-Wheel Hop: Vehicle speed sensitive, mechanical vibration. The wheel hop generates rapid up-down movement in the steering wheel. The vibration is most noticeable in the 20 - 40 mph (32 - 64 km/h) range. The wheel hop will not cause vibration below 20 mph (32 km/h). Wheel hop is caused by a tire/wheel that has a radial runout of more than
0.045 of-an-inch (1.14 mm). If wheel runout is acceptable and combined runout cannot be reduced by repositioning the tire on wheel, replace tire. TB-Tire/Wheel Balance: Vehicle speed sensitive, mechanical vibration. Static tire/wheel unbalance will not cause vibration below 30 mph (46 km/h). Dynamic tire/wheel unbalance will not cause vibration below 40 mph (64 km/h). TLR-Tire/Wheel Lateral runout: Vehicle speed sensitive, mechanical vibration. The runout will not cause vibration below 50 - 55 mph (80 - 88 km/h). Excessive lateral runout will also cause front-end shimmy. TW-Tire Wear: Vehicle speed sensitive, audible vibration. Abnormal tire wear causes small vibration in the 30 - 55 mph (88 km/h) range. This will produce a whine noise at high speed. The whine will change to a growl noise when the speed is reduced. W-Tire Waddle: Vehicle speed sensitive, mechanical vibration. Irregular tire uniformity can cause side-to-side motion during speeds up to 15 mph (24 km/h). If the motion is excessive, identify the defective tire and replace it. UAJ-Universal Joint (Drive Shaft) Angles: Torque/vehicle speed sensitive, mechanical/audible vibration. Incorrect drive shaft angles cause mechanical vibration below 20 mph (32 km/h) and in the 70 mph (112 km/h) range. The incorrect angles can also produce an audible vibration in the 20 - 50 mph (32 -
80 km/h) range. Caster adjustment could be required to correct the angles. UJ-Universal Joints: Engine torque/vehicle speed sensitive, mechanical/audible vibration. If the U-joint is worn it will cause vibration with almost any vehicle speed/engine torque condition. DSY-Drive Shaft and Yokes: Vehicle speed sensitive, mechanical/audible vibration. The condition will not cause vibration below 35 mph (56 km/h). Excessive runout, unbalance or dents and bends in the shaft will cause the vibration. Identify the actual cause and repair/replace as necessary. WB-Wheel Bearings: Vehicle speed sensitive, mechanical/audible vibration. Loose wheel bearings cause shimmy-like vibration at 35 mph (56 km/h) and above. Worn bearings will also produce a growl noise at low vehicle speed and a whine noise at high vehicle speed. The wheel bearings must be adjusted or replaced, as applicable. AN-Axle Noise: Engine torque/vehicle speed sensitive, mechanical/audible vibration. The axle will not cause mechanical vibration unless the axle shaft is bent. Worn or damaged axle pinion shaft or differential gears and bearings will cause noise. Replace the defective component(s) as necessary. SSC-Suspension and Steering Components: Vehicle speed sensitive, mechanical vibration. Worn suspension/steering components can cause mechanical vibration at speeds above 20 mph (32 km/h). Identify and repair or replace the defective component( s). EA-Engine Driven Accessories: Engine speed sensitive, mechanical/audible vibration. Vibration can be caused by loose or broken A/C compressor, PS pump, water pump, generator or brackets, etc. Usually more noticeable when the transmission is shifted into the NEUTRAL position and the engine speed (rpm) increased. Inspect the engine driven accessories in the engine compartment. Repair/replace as necessary. ADB-Accessory Drive Belts: Engine speed sensitive, audible vibration. Worn drive belts can cause a vibration that produces either a droning, fluttering or rumbling noise. Inspect the drive belt(s) and tighten/ replace as necessary. DEM-Damaged Engine or Transmission Support Mounts: Engine speed sensitive, mechanical/ audible vibration. If a support mount is worn, noise or vibration will occur. Inspect the support mounts and repair/replace as necessary. ES-Exhaust System: Engine speed sensitive, mechanical/audible vibration. If loose exhaust components contact the vehicle body they will cause noise and vibration. Inspect the exhaust system for loose, broken and mis-aligned components and repair/replace as necessary.
"L.W.(Bill) Hughes III" wrote in message news: snipped-for-privacy@cox.net...
I had a noise similar to the bonus question. It turned out to be shock absorbers. When did you last change them? My 2000 has about the same number of miles on it.
Reach under the front tire and grab the shock tube and give it a yank. You might hear the rattle sound.
In any case, I doubt that the factory shocks last 130K.
Paul Nelson
in article 15GdnYE0L_BTd9rYnZ2dnUVZ snipped-for-privacy@comcast.com, James at snipped-for-privacy@nospamfdn.com wrote on 10/31/06 6:31 PM:
Bad steering dampers don't cause shimmy. Good ones just mask the real cause.
I'm guessing he's got a worn or loose track bar. 2000 GC has the solid axle up front, right?
The rear rumble could be just road noise, does it change in pitch with vehicle speed, or does it stay on a constant pitch? center rear of the car could be rear diff. Check your driveshaft U joints for wear, have your diff inspected.
I find my CJ7 has always been super twitchy and it reacts badly or better said too fast to cross wind changes. I'll bet if I put a stabilizer shock on my steering this would go away....
Same for the trails. I am thinking I could have avoided a bunch of blisters on my hands running ice/mud/dirt trails with a steering shock.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >
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