23-NA-142

Bulletin No.:
Service Bulletin
Date:
23-NA-142
September, 2023
TECHNICAL
Subject:
No Forward Gear When Shifting from Park to Drive and/or Reverse to Drive
Brand:
Model:
Chevrolet
Express
GMC
Savana
Model Year:
from
to
2017
2023
VIN:
from
to
Engine:
Transmission:
6L90 (MYD)
Involved Region or Country
North America
Condition
Some customers may comment that the vehicle won’t move forward after shifting into
Drive from Park or Reverse.
Some customers may also comment that reverse appears to work properly.
Note: Once moving in drive. There should be no concern until the next shift cycle.
Cause
6404748
This condition may be caused by a Spacer Plate in the valve body that does not meet the
specification for chamfer across the entire circumference of the coined check ball seat.
Copyright 2023 General Motors LLC. All Rights Reserved.
Page 2
September, 2023
Bulletin No.: 23-NA-142
6404809
– The seat for the check ball is out of spec relative to coin depth. This potentially can
cause burrs, dents, or dings, which could cause the plastic check ball to wear
prematurely.
Note: School buses, some of which shift to Park at each student stop, may exhibit the
earliest signs of failure.
– The #1 check ball has a high duty cycle and when combined with the issue, there is a
possibility for the check ball to wear and then become stuck or pass through the spacer
plate.
6404322
– As indicated in the graphic above, the check ball circled in RED has prematurely worn
down. It should be the same diameter as the check ball circled in GREEN.
Correction
Replace the spacer plate and check ball.
Bulletin No.: 23-NA-142
September, 2023
Page 3
Important: Service agents must comply with all
International, Federal, State, Provincial, and/or
Local laws applicable to the activities it performs
under this bulletin, including but not limited to
handling, deploying, preparing, classifying,
packaging, marking, labeling, and shipping
dangerous goods. In the event of a conflict between
the procedures set forth in this bulletin and the
laws that apply to your dealership, you must follow
those applicable laws.
Service Procedure
Refer to Control Valve Lower Body and Upper Body
Replacement in the Service Manual.
Parts Information
Causal
Part
Description
Part Number
Qty
X
PLATE PKG,
C/VLV BODY
SPCR (INCLUDES
C/VLV BODY
BALL CHK)
24272467
1
N/A
FLUID,
TRANSMISSION
Refer to EPC
As
Required
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
8463870
Control Valve Lower Body and Upper Body Replacement
Use the Published Labor
Operations Time
Version
1
Modified
Released September 15, 2023
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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