Bulletin No.: PIP5943
Published date: 10/19/2023

Preliminary Information
PIP5943 Diagnostic Aids for 8 Speed Transmissions With Shift
Concerns
Models
Brand:

Model:

Model Years:

VIN:
from to

Engine: Transmissions:

Cadillac

ATS

2016 - 2019

All

All All

M5N, MNU

Cadillac

CTS

2016 - 2019

All

All All

M5N, M5U

Cadillac

CT6

2016 - 2018

All

All All

M5N, M5X

Cadillac

CT4

2020 - 2024

All

All All

M5N, MHA

Cadillac

Escalade

2015 - 2020

All

All All

M5U

Chevrolet Camaro

2016 - 2023

All

All All

M5T, M5U

Chevrolet Corvette

2015 - 2018

All

All All

M5U

Chevrolet Colorado (VIN S/T)

2017 - 2023

All

All All

M5T

Chevrolet Express

2017 - 2024

All

All All

M5U

Chevrolet Silverado

2015 - 2018

All

All All

M5U, M5X

Chevrolet Silverado 1500 (New Model)

2019

All

All All

MQE

Chevrolet Silverado 1500

2020 - 2021

All

All All

MQE

Chevrolet Silverado 1500- LTD (RPO J21, VIN Digit 5 = A/D)

2022

All

All All

M5X

Chevrolet Silverado 1500- LTD (RPO J22, VIN Digit 5 = W/Y)

2022

All

All All

M5X, MQE

Chevrolet Silverado 1500

2022 - 2023

All

All All

MQE

GMC

Canyon

2017 - 2023

All

All All

M5T

GMC

Sierra

2015 - 2018

All

All All

MQE

GMC

Sierra 1500 (New Model)

2019

All

All All

MQE

GMC

Sierra 1500

2020 - 2021

All

All All

MQE

GMC

Sierra 1500 - Limited (RPO J21, VIN Digit 5 = 8/9)

2022

All

All All

M5X, MQE

GMC

Sierra 1500 - New (RPO J22, VIN Digit 5 = H/U)

2022

All

All All

M5X, MQE

GMC

Sierra 1500

2023

All

All All

MQE

GMC

Savanna

2017 - 2023

All

All All

M5U, MQD

GMC

Yukon

2015 - 2020

All

All All

M5U

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Involved Region or Country:

North America

Condition:
Cause
Correction:

There may be complaints of hard or harsh shifts on 8 speed transmissions.
Diagnostic aids for improving shift quality .

First if there is a hard 1-2 shift felt on the rst 1-2 shift of the day, it is to be considered normal as there is a clutch
purge being performed at this time and no repair attempts should be performed. Please refer to bulletin 16-NA361.
On low mileage vehicles, meaning vehicles less than 1 year old and having less than 3000 miles on the odometer,
if a hard shift or a shift the customer may nd to be objectionable, the rst step is to follow bulletin 16-NA-019.
While following 16-NA-019, please do not use the clutch volume or the spring learns that can be found in GDS2.
These are very misleading, as they can cause the Technician to believe the learn has completed when it may not
have. These parameters are algorithmically based to change once the conditions have been met twice for the
clutch or spring learn, it does not mean that the clutch or spring has completely nished the learn. Drive the
vehicle until you can feel the di erence in the shift to determine if the clutch learn is progressing.
On vehicles with greater than 3000 miles, or on vehicles that have objectionable shifts once bulletin 16-NA-019
has been completed the next direction should be to remove the transmission pan and inspect for debris. If there
is not an unreasonable amount of debris based on mileage then the valve body should be replaced and bulletin
16-NA-019 followed again.
If the Debris is excessive, OR the condition remains following the valve body replacement, and after performing
16-NA-019; the next step is removal of the transmission and inspecting the clutch pack travel and resetting as
necessary.
Generally speaking, setting the clutch pack travel to the tighter end of the range tends to produce a more
appealing shift to the customer. During tear down the steels should be inspected for uneven and excessive wear
and replaced as needed, if there is damage or distress seen to the friction discs .
Also, when dealing with Hard or uncomfortable garage shifts that 16-NA-019, or the valve body does not correct,
it has determined that setting the transmission end play toward the tight end of the speci cation (.008”-.012”) has
proven to be an e ective repair
If there are signs of overheating, the technician should verify the TBV valve operation using a laser thermometer
to measure inlet and outlet temperatures of the cooler by measuring the lines at di erent locations.
Also, If the speed sensors were just replaced and the Service Fast Learn fails for excessive vehicle speed, or If
P0717, P0722, P0746 and/or P0796 also sets the Speed sensors should be inspected for the proper orientation as
seen in SI, Meaning the smaller portion of the conduit should be facing the rear of the unit
Please note the pictures below
Incorrect Installation

Correct Installation

Warranty Information
For vehicles repaired under the Bumper-to-Bumper coverage (Canada Base Warranty coverage), use the following
labor operation. Reference the Applicable Warranties section of Investigate Vehicle History (IVH) for coverage
information.

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.

Version History
Version
Modi ed

1
10/19/2023 - Created on.

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