Bulletin No.:

Service Bulletin

Date:

19-NA-217
March, 2020

TECHNICAL
Subject:

Manual Transmission Stalling, Clutch Chatter and/or Hard Shifting into 1st Gear or
Reverse; Automatic Transmission Vibration on Launch and/or Engine Noise

Brand:

Model:

Chevrolet

Corvette

Model Year:

VIN Breakpoint

from

to

2014

2019

Involved Region or Country

Condition

from

to

Engine:

Transmission:

6.2L (LT1, LT4)

6L80 Automatic
(MYC), 8L90
Automatic (M5U)
or Manual

United States, Canada, Mexico, Europe, Russia, Middle East, Japan, Thailand
Important: If the vehicle came in with a rattle noise coming from the front of the vehicle
when the engine is running at slower engine speeds and no other concerns, refer to
Service Bulletin 18-NA-268.
Some customers may comment on any of the following conditions:
Note: On Automatic Transmission equipped vehicles, this may also happen after the
driveline was replaced for another reason.
– For Manual Transmission equipped vehicles:
• Stalling
• Clutch chatter
• Hard shifting into 1st gear or Reverse
– For Automatic Transmission equipped vehicles:
• Vibration on takeoff
• Clunk noise

Cause

This condition may be caused by excessive crankshaft endplay associated with a
damaged thrust bearing.
– Please use following information before considering an engine or crankshaft
replacement.

Correction

If a vehicle comes in with the conditions listed above, refer to the Service Procedure
below.

Note: Complete the SI diagnostics and the Cost
Comparison Worksheet for Assembly Repair vs
Replacement to determine if the engine requires a
repair or replacement. DO NOT the replace engine
assembly for this concern. Only replace the engine
assembly if other damage is found.

Copyright 2020 General Motors LLC. All Rights Reserved.

Page 2

March, 2020

Bulletin No.: 19-NA-217

5403465

Example of a good thrust bearing face.

Service Procedure
Important: Follow the service procedures outlined in
Service Bulletin 18-NA-268 for DSA inspection and
possible repair.
1. Validate the crankshaft endplay is within
specification (0.0015-0.0086 (0.040-0.220 mm).
⇒ If endplay is found to be out of specification,
remove the engine oil pan and inspect for
possible crankshaft thrust bearing and/or
crankshaft wear.
2. Start with removing the middle thrust main
bearing cap.

Bulletin No.: 19-NA-217

March, 2020

Page 3

5403464

3. Inspect the thrust bearing for wear on one side and
crankshaft on the corresponding mating surface.
The graphic above shows an example of a
damaged thrust bearing.
Note: It is not necessary to replace the engine
assembly for this condition.

Causal
Part

Description

N/A

BOLT, CR/SHF
BRG CAP
(M10X2X82)
(LT1/LT4)

⇒ If wear is evident (3 vertical channels worn off),
it will be necessary to replace the crankshaft,
connecting rods and main bearings.
4. Refer to Crankshaft and Bearing Removal in SI.
If bearing damage is found and if the vehicle is
equipped with a dry sump system, it will be necessary
to replace the oil tank with lines and oil cooler.

N/A

Parts Information
Causal
Part

Description

Part
Number

Qty

X

CRANKSHAFT
(LT1)

12674745
(EXC Z52)

1

X

CRANKSHAFT
(LT1)

12674744
(Z52)

1

X

CRANKSHAFT
(LT4)

12674743

N/A

BOLT, CR/SHF
BRG CAP
(M10X2X96)
(LT1/LT4)

11548075
1
11546565

SEAL, CR/SHF
FRT OIL
(LT1/LT4)

12693255

N/A

SEAL, CR/SHF
RR OIL (LT1/LT4)

89060436

N/A

BEARING KIT,
CR/SHF
(LT1/LT4)

12656814

BEARING KIT,
CONN ROD
(LT1/LT4)

12683811

BEARING, CLU/
PILOT (Manual
Transmission
Only) (LT1/LT4)

12557583

TNK, ENG OIL
(LT1/LT4 Dry
Sump Only Z52)

12680701

HOSE, AUX ENG
OIL TK INL

23299434

N/A

N/A

N/A
1

N/A

N/A

Qty
1

BOLT, CR/SHF
BRG CAP
(M8X1.25X25
HEX FLANGE)
(LT1/LT4)

1
11548076

Part
Number

1

1
1

1

1

1

1

Page 4

March, 2020

Causal
Part

Description

N/A

HOSE, AUX ENG
OIL TK OTLT

N/A

BOLT, A/TRANS
FLEX PLT
(M11X1.5X19)
(LT1/LT4)

N/A

OIL, Engine

N/A

FILTER, OIL

Part
Number

Bulletin No.: 19-NA-217

Qty
1

23299435

1
11547118

Refer to EPC

Warranty Information
For vehicles repaired under the Powertrain coverage,
use the following labor operation. Reference the
Applicable Warranties section of Investigate Vehicle
History (IVH) for coverage information.
Labor
Operation
4087158*

Description

Labor Time

Replace Crankshaft,
Crankshaft Main Bearings
and Connecting Rod
Bearings

24.1 hrs

*This is a unique Labor Operation for bulletin use only.

Version

2

Modified

Released February 4, 2020
March 24, 2020 – Added CRANKSHAFT (LT1) 12674744 (Z52) to the Parts Information
section and corrected P/N 11547188 to 11547118.

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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