Bulletin No.:

Service Bulletin

20-NA-116

Date:

February, 2023

INFORMATION
Subject:

Available Top Speed Changes
This bulletin replaces PIP5638A. Please discard all versions of PIP5638.

Model Year:

Brand:

Model:

Chevrolet

Silverado 4500HD/
5500HD/6500HD

from

to

2019

2022

VIN:
from

Engine:

Transmission:

All

All

to

Involved Region or Country

North America

Condition

Some customers may comment on wanting to change the current top speed on the
vehicle.

Cause

Based on how the vehicle was ordered, the truck comes with a standard top speed.

Correction

The standard top speed can be changed 2 ways outlined below.

Note: Any changes made to the Maximum Standard
(as built) Speed will be the responsibility of the
customer.

Option 1
Rear
Axle
Ratio

Standard Max
Geared Road
Speed

Optional
Geared
Road Speed

RPO
"Govenor
Up" Speed

4.1
(RPO
066)

79

79

N/A

4.3
(RPO
092)

75

79**

9D6

4.56
(RPO
005)

70

75*

9D7

4.88
(RPO
008)

65

70*

9B9

* — All 141" WB vehicles (FQT) will be limited to 65 MPH at
4.88, 70 MPH @ 4.56 & 75 MPH @ 4.30 RAR.
** — All 141" WB vehicles (FQT) will be limited to 65 MPH
at 4.88, 70 MPH @ 4.56 & 75 MPH @ 4.30 RAR. 4X4 reg
cab (165" WB - ED9) will be limited to a top speed of 75
MPH. 4X4 crew cab (175" WB - FNV) will be limited to a top
speed of 75 MPH.
*** — Trucks equipped with XDV/YAP tires (H-rated) limited
to max speeds of 75 MPH (N/A with 9D6).

Copyright 2023 General Motors LLC. All Rights Reserved.

First option (See chart above) is to add calibration for
the appropriate RPO. This will allow a 5 MPH increase
with no hardware.

Page 2

February, 2023

Bulletin No.: 20-NA-116

Option 2
Possible Rear Axle Changes
Change From

Change To

4.88

4.10

4.88

4.30

4.88

4.56

4.56

4.10

4.56

4.30

Note: There may be other concerns where a customer/
dealer may want to change from a lower (numerical)
RAR to a higher RAR to improve towing performance.

Possible Rear Axle Changes
Change From

Change To

4.10

4.56

4.10

4.88

4.30

4.56

4.30

4.88

4.56

4.88

Note: This is only for 4x2 trucks (4x4 is only 4.30
all the time).
Second option (See chart above), changing gears for
rear axle ratio and calibration will allow a top speed
change greater than 5 MPH. Contact Techline for
Calibrations.

Version

3

Modified

Released June 01, 2020
Revised February 08, 2021 — Added additional bullet point at end of Option 1 Chart.
Revised February 13, 2023 — Added the 2022 Model Year.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.

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