PIP5943

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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