2021-2025 Jeep Wrangler Front End Shimmy TSB S1819000004

Owners of 2021-2025 Jeep Wrangler vehicles may experience a "Shimmy Felt In Front End" when driving over road irregularities such as expansion joints, potholes, or bumps. This condition, often perceived as a shimmy in the steering wheel, is addressed by Technical Service Bulletin (TSB) S1819000004, released in February 2025. This bulletin provides a detailed diagnostic and repair procedure to resolve the Jeep Wrangler front end shimmy.

Symptoms

The primary symptom described in TSB S1819000004 is a "Shimmy Felt In Front End." This manifests as a noticeable vibration or shimmy in the steering wheel, typically occurring after the vehicle encounters an uneven road surface. This can be an unsettling experience for drivers and indicates a potential issue with the vehicle's steering or suspension components.

Important Warnings for Owners

Owners should be aware of specific instructions provided in the TSB to ensure proper diagnosis and repair:

• Do not replace the steering damper unnecessarily: If the current steering damper matches the latest Mopar service replacement part, it should not be replaced. Instead, the damper should be purged on the vehicle using the specified Steering Cycling instructions.
• Warranty repairs are not authorized by this document: The TSB explicitly states, "This document does not authorize warranty repairs." This communication serves as a record of past experiences and provides guidance for technicians, but it does not guarantee warranty coverage for the repair.

Initial Repair Checks and Diagnosis

Before proceeding with any damper-related repairs for a Jeep Wrangler front end shimmy, technicians are instructed to perform several initial checks:

1. Tire Pressure and Condition: Ensure all tire pressures are correct, especially considering temperature changes. Inspect tires for any signs of wear or damage. Replace tires as needed.
2. Steering Damper Part Number: The part number of the currently installed steering damper must be inspected. This step is crucial for determining the subsequent repair path.

Steering Damper Inspection and Repair Procedure

Depending on the steering damper inspection, one of two paths is followed to address the "Shimmy Felt In Front End":

• If the damper matches the latest Mopar service replacement part: Do not replace the damper. Instead, purge the damper while it is still installed on the vehicle using the Steering Cycling instructions outlined below. After purging, proceed to step 4 of the overall repair process.
• If the damper does NOT match the latest Mopar service replacement part: The damper must be replaced with the latest revision part. Before installation, perform a specific "bicycle pump" purge cycle procedure. This involves placing the base cup side of the damper on the floor and pumping it up and down 5 times, as fast as possible, from full compression to full extension. A stud or screwdriver can be used on the bushing for added grip. Refer to the Star Parts Catalog for the latest part information and diagnostic videos for steering damper installation. It is critical to use new fasteners and ensure the damper is installed with the base cup towards the wheel and facing down, following all orientation instructions.

After a new damper is installed, or an existing one is purged, perform a 25 lock-to-lock steering procedure and drive the vehicle, making as many turns as possible. This helps to further purge air from the damper. The vehicle should then be evaluated on the highway for any "SUSTAINED shimmy." If a "SUSTAINED shimmy" still exists, repeat the 25 lock-to-lock procedure to ensure all air is purged.

Steering Cycling Damper Purge Procedure

The Steering Cycling procedure is a critical step for purging air from the steering damper, whether it's a new installation or an on-car purge for an existing damper. The steps are as follows:

1. Start the vehicle with the tires pointed straight ahead and the engine running.
2. Turn the steering wheel to the right until it reaches its stop, at a rate of approximately 180 degrees per second.
3. Turn the steering wheel to the left until it reaches its stop, maintaining the same rate.
4. Return the steering wheel to the straight ahead position.
5. This completes one cycle. Repeat this process for a total of 25 cycles.
6. Test drive the vehicle to confirm that the Jeep Wrangler front end shimmy is no longer present.
7. If the shimmy is still present but has improved, repeat the entire steering cycling procedure.

Additional Checks for Persistent Shimmy

If the Jeep Wrangler front end shimmy persists after the damper inspection, replacement, and purge procedures, additional items should be checked:

1. Wheel Alignment: Verify the alignment, specifically ensuring the Total Toe is as far "IN" or "POSITIVE" as possible while remaining within specifications (approximately 0.35 degrees total and 0.17 degrees individual).
2. Road Force Tire Balance: Perform a road force tire balance. Ensure there are no "highfliers" (tires with excessive road force variation) and that the front tires are balanced to be as low as possible in terms of road force.

This comprehensive approach, detailed in TSB S1819000004, aims to effectively diagnose and resolve the "Shimmy Felt In Front End" condition in affected Jeep Wrangler vehicles.

NHTSA ID: 11014268