Exhaust Noise/Moan/Drone/Resonance/Vibration at Idle While in Drive with Foot on Brake (Modify Rear Bodyside Exhaust Hanger Brackets)

Some customers may comment on moan, drone, vibration and/or resonance type noise at idle while in drive and with their foot on the brake. This noise may be heard as an oscillating type sound that is heard in the vehicle cabin and is more pronounced when the vehicle is warmed up.

Technicians are to modify the left and right rear bodyside exhaust hanger brackets.

1. Loosen the nuts that attach the front flange of the muffler assembly to the converter assemblies.



2. While supporting the muffler assembly, disconnect the front and rear muffler isolators and lower the rear portion of the muffler assembly enough to gain access to the rear bodyside exhaust hanger brackets.
3. Remove the left and right rear hanger brackets.




Tip
Use a paint marker to mark the amount of material to be grinded.

4. Modify the rear bracket by elongating each attachment hole by 4.5 mm (0.18 in). For each attachment hole, grind away 4.5 mm (0.18 in) of material on the top side of the hole only so that the bracket can be reinstalled in a lower position.
5. Spray Rubberized Undercoating, P/N 12378398 (in Canada, P/N 10952414) or equivalent, on the brackets to prevent corrosion.
6. Install the bracket to the vehicle with bracket all the way in a downward position while tightening the nuts.
7. Tighten the muffler assembly flanges using an alternating torque sequence (LH inboard nut, RH inboard nut, LH outboard nut, RH outboard nut). Refer to SI for torque specifications.
8. Tighten the front flange of the muffler to the converter assembly.