Bulletin No.: PIT5403H
Published date: 05/25/2021

Preliminary Information
PIT5403H Various Vehicle Handling Concerns Suspension Noise or
Damaged Suspension Components Due to Vehicle Modi cations
Models
Brand:

Model:

Model Years:

VIN:
from

to

Engine:

Transmissions:

Cadillac

Escalade EXT

2007 - 2013

All

All

All

All

Cadillac

Escalade

2007 - 2021

All

All

All

All

Chevrolet

Avalanche

2007 - 2013

All

All

All

All

Chevrolet

Silverado

2007 - 2021

All

All

All

All

Chevrolet

Suburban

2007 - 2021

All

All

All

All

Chevrolet

Tahoe

2007 - 2021

All

All

All

All

GMC

Sierra

2007 - 2021

All

All

All

All

GMC

Yukon Model

2007 - 2021

All

All

All

All

Supersession Statement
This PI was superseded to add model years. Please discard PIT5403G.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition / Concern
Some owners may comment on various handling, vehicle dynamics concerns, noises from the
suspension or underbody, or issues related to damaged suspension components.
These concerns may occur if the vehicle’s suspension system has been modified by using
aftermarket suspension lift or lowering kits, or making modifications to the vehicle including
adjusting components beyond factory specifications such as, but not limited to adjusting
torsion bar suspensions to change suspension height and/or aftermarket wheels and/or tires
installed.

Recommendations / Instructions
Before any in-depth diagnostics are performed, be aware that various issues could occur if
the vehicle has been modified and inform the customer the conditions noted may not be
covered under warranty.
Most of the larger lift kits are easy to identify because of the major modifications made as
compared to a stock vehicle.
This bulletin will help identify some of the smaller changes that can still drive concerns.
If there is any question regarding potential modifications, compare the truck with concerns
to a like vehicle looking for modified components.
Inspect for installed aftermarket suspension components such as but not limited to the
examples below:

1. Aftermarket lift kit block

2. Aftermarket lift kit blocks removed from a truck

3. Aftermarket coil spring spacer

4. Aftermarket lift kit blocks installed

5. Aftermarket coil spring spacer

6. Aftermarket rear leaf spring lift block
Inspect for improperly adjusted torsion bars (shown below #7) resulting in improper Zheight adjustments. For this example, the Z-height for this truck would be above the
specifications but there is not an actual lift kit installed.

Below is an example of lift provided by improperly adjusting the z-height. In this example,
the front suspension has been raised about 3 inches.

If the torsion bars have been improperly adjusted as shown above, also inspect for contact
between the upper control arm (shown below #9) and the frame (shown below #10). If
contact is found inspect the upper ball joint for looseness, as it may have been damaged by
the modification.

Below is an example of a vehicle sitting at factory ride height (A) with 25 mm gap between upper control arm and
bump stop, and a vehicle that has had the torsion bar adjusted (B) has a 5 to 10 mm gap between upper control
arm and bump stop.

When determining if a vehicle has been modified additional clues can be found by inspecting
for quality control marks (shown below #8)from the factory that are not aligned (especially
on new trucks):

Note: The green quality control marks do not line up indicating this vehicle has been
tampered with.

11. Aftermarket Lift Kit Block installed

12. Aftermarket Coil Spring Spacer installed

Warranty Information
Any concerns or damage that occurs as a result of vehicle modification may not be covered
under the Terms of the New Vehicle Limited Warranty. Reference the latest version of TSB
09-00-89-016 - Warranty Administration – Labor Operation 0600014 – Suspected Tampering
or Vehicle Modifications if needed.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is
resolved without completing every step, the remaining steps do not need to be performed.

Additional SI Keywords
align alignment axle ball bar break broke broken control C0710 damage drag end front high inch inches inner
joint kit left lift link loose low lower lowering modi ed noise outer plow rack rear right rod snow stabilitrak
stability steer steering susp suspension sway tcs tie tire tires torsion traction turn underbody unwant unwanted
upper wear wheel wheels worn

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