ride height

[mark7069]

I have a 2006 GMC Sierra Classic Special Edition with the factory 20" wheels. The right rear sits about an inch and a half higher than the left and the right front sits about a half an inch higher than ther left. Could this be a torsion bar adjustment issue? The truck has 13K miles and is only 9 months old.

[TBLAZER]

I have a 2006 GMC Sierra Classic Special Edition with the factory 20" wheels. The right rear sits about an inch and a half higher than the left and the right front sits about a half an inch higher than ther left. Could this be a torsion bar adjustment issue? The truck has 13K miles and is only 9 months old.

GM has a bulletin to correct this condition,Bulleting #06-03-06-005A.

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Document ID# 1887100

 

Subject: Vehicle Lean - Left Front Sits Low or Right Rear High (Add Spacer Between Left Rear Spring Pack and Axle) #06-03-06-005A - (01/12/2007)

 

Models: 1999-2007 Chevrolet Silverado (Classic) 1500 (½ Ton) Series

 

1999-2007 GMC Sierra (Classic) 1500 (½ Ton) Series

 

with Two-Wheel Drive

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This bulletin is being revised to update the models to reflect that bulletin only applies to 1500 (½ Ton) Series. Please discard Corporate Bulletin Number 06-03-06-005 (Section 03 -- Suspension).

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Condition

Some customers may comment that their vehicle appears to lean. In most cases, the vehicle will sit low left front or high right rear.

 

Correction

Measure fender wheel-opening heights, front and rear, to quantify vehicle lean. Fender wheel-opening heights are related to, but distinct from, trim height (a.k.a. Z and D height). The front wheel-opening height is known as P height, and the rear wheel-opening height is know as R height. The P and R heights are not set at the factory, nor is a specification given for them. However, they are the most direct and repeatable measurement of what a customer would see as the vehicle leaning. Perform the following before measuring the fender wheel-opening heights:

 

• Make sure the vehicle is on a level surface, such as an alignment rack.

 

• Set the tire pressures to the pressure shown on the certification label. Refer to Label - Vehicle Certification in General Information.

 

• Check the fuel level. Add additional weight if necessary to simulate a full tank.

 

• To ensure proper weight distribution, make sure the rear storage compartment is empty.

 

• Close the doors and hood.

 

P Height and R Height Measurements

P height and R height are measured the same way. They are the distance from the ground to the highest point on their respective wheel-opening, going through the center of their respective wheel. Record the measurement on the repair order.

 

If the difference from left to right for P and R height is 15 mm (0.59 in) or less, no repairs are suggested as the vehicle is within specification. If the difference exceeds 15 mm (0.59 in) for either measurement, install the spring spacer to the left rear side of the vehicle following the procedure below.

 

Raise and support the vehicle.

Support the rear axle.

Remove the U-bolt nuts, remove the U-bolts and anchor plate. Discard the U-bolts. DO NOT discard the nuts or anchor plate.

Remove the lower shock nut and bolt.

Raise the vehicle or lower the axle enough to allow for installation of the spacer. Install the spacer, P/N 15872657.

Lower the vehicle or raise the axle.

Install the lower shock nut and bolt.

Tighten

Tighten to 95 N·m (70 lb ft).

 

Install the anchor plate, new longer U-bolts, P/N 15872655, and nuts.

Tighten

Tighten the nuts to 72 N·m (53 lb ft).

 

Remove the axle support and lower the vehicle.

Re-check the P and R heights in the previous location. Record these readings on the repair order.

After all measurements are done, perform a road test and check headlight aim.

If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

 

Parts Information

Part Number

Description

Qty

 

15872655

Rear Spring Spacer

1

 

15872657

Rear Spring U-Bolt

2