Wheels/Tires/Driveline - Highway Speed Vibration
NUMBER: 22-003-03GROUP: Tires & Wheels
DATE: June 27, 2003
SUBJECT:
Vibration at Highway Speeds
OVERVIEW:
This bulletin involves diagnosis and corrective information for vehicles with a smooth road shake condition.
MODELS:
2002 (DR) Ram Truck
SYMPTOM/CONDITION:
Some vehicles may exhibit a vibration at highway speeds on smooth roads. The following is a diagnostic and repair procedure recommended for vehicles with this condition.
EQUIPMENT REQUIRED:
Wheel Balancer Capable of Static and Dynamic Balancing
DIAGNOSIS/REPAIR:
Visual Inspection of the vehicle is recommended prior to the initial test drive. Raise vehicle on a suitable hoist and inspect the following items: Verify correct (original equipment) wheels and tires. Inspect tires and wheels for damage, mud packing and unusual wear; correct as necessary. Check and adjust tire pressure to the recommended pressure. If vehicle is in pre-delivery condition, do not remove the matchmount stickers from the wheel and tire. Road Test on a smooth road (preferably asphalt) for at least 5 miles to warm tires and remove flat spots. Lightly place hands on steering wheel at the 10:00 and 2:00 positions while slowly speeding up and down from 55 to 70 MPH (where speed limit permits). Note amount of shake and at what speed it occurs in: steering wheel, seat, floor, etc.. Shake occurring between 65 and 70 m.p.h. is typically caused by wheel and tire issues. Shake in other speed ranges is likely caused by other components. Rule out vibrations due to powertrain or brakes by: lightly apply brakes; if vibration occurs or is enhanced, vibration is likely due to causes other than tire/wheel assemblies. Shift transmission into neutral while vibration is occurring; if eliminated, vibration is likely due to causes other than tire/wheel assemblies.
Check rear driveshaft for proper matching.
1. The rear driveshaft should have a yellow paint mark near the rear U-joint. The companion flange on the rear axle should be marked in blue or yellow paint. Ensure that the paint marks on the driveshaft and companion flange are aligned. If the paint marks on the driveshaft and companion flange are not aligned, remove the U-joint from the companion flange and install it with the paint marks lined up.
Check for wheel to hub pilot error
2. If match mounting stickers are not on the wheels and/or tires, proceed to Balancing. If match mounting stickers are still on the wheels and/or tires, do the following:
Raise vehicle off ground. Rotate wheel/tire assemblies so that the match mount stickers are at the top center (12:00) position Loosen, but do not remove the lug nuts. Break the wheel free from the hub. While keeping the match mount stickers at 12:00, tighten the lug nuts in a star pattern to 120 ft. lbs.
Balance Wheel/Tire Assemblies
NOTE:
Balance equipment must be calibrated and maintained per equipment manufacturer's specifications.
3. Using a conventional balancer (no road force measurement): Before removing assemblies from the vehicle, mark each tire with a "V" or triangle at the valve stem location. Mark each tire with the position (LF, RF, LR, RR) For each wheel position, remove the two lug nuts on either side of the valve stem first, and paint mark the ends of these studs, so the wheel can be installed in the same position.
4. Record the original balance weight amounts and clock positions with the valve stem at 12:00. Balance assemblies dynamically and statically to within 0.25 ounce.
5. Loosen the assembly on the balancer, and rotate it 180 degrees on balance equipment and check balance. Variation should not be more than 0.125 ounce. If variation is more than 0.125 ounce, balancing equipment could be malfunctioning.
NOTE:
If a Hunter GSP 9700 with Road Force Measurement is available, measure balance and road force variation as follows:
6. Before removing assemblies from the vehicle, mark each tire with a "V" or triangle at the valve stem location. Mark each tire with the position (LF, RF, LR, RR). For each wheel position, remove the two lug nuts on either side of the valve stem first, and paint mark the ends of these studs, so the wheel can be installed in the same position.
7. Record the original balance weight amounts and clock positions with the valve stem at 12:00. Set the GSP 9700 to the correct tire type (P or LT). Use a cone behind the wheel to pilot the assembly on the machine. This will use the same wheel pilot that the hub on the vehicle uses. Measure balance and force variation. Note the required balance weights and force variation values.
8. Loosen the assembly on the balancer, and rotate it 180 degrees and check balance. Balance weights should be within 0.25 ounce of the first reading, and R1H should be within 4 lbs. of the first reading. If there is more variation than 0.25 ounce for balance or 4 lbs for force variation, the wheel may not be properly piloted or the equipment could be malfunctioning. Mark the high point of force variation. Record the value of R1H.
9. If Radial 1st Harmonic variation (R1H) for the assembly exceeds 30 lbs, dismount the tire, and measure the rim runout on the bead seats using the "measure bare rim" function. Rim measurement on the outside flanges is not accurate. Follow the Hunter procedure to match mount the wheel and tire. Make sure that the location of the high force is marked on the tire. Record the final R1H value after match mounting.
10. After all four wheels & tires have been balanced and match mounted (if necessary), install them on the vehicle, with the high point at 12:00. Tighten the lug nuts in a star pattern, keeping the force variation high point at 12:00.
11. Refer to the procedure in the DR service manual, Section 22 to measure and minimize tire/wheel runout.
Radial Runout
POLICY:
Reimbursable within the provisions of the warranty using diagnostic labor operations for actual labor time. The Operation Diagnostic labor operations can be located in the 80/90 - Special Services tab in the Labor Operations Manual. Usage of these operations must follow the guidelines outlined in the Global Warranty Administration Manual, pages WP21 - WP31.