Manual Transmission Stalling, Clutch Chatter and/or Hard Shifting into 1st Gear or Reverse; Automatic Transmission Vibration on Launch and/or Engine Noise – 2014-2019 Chevrolet Corvette

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Service Bulletin Bulletin No.: 19-NA-217
Date: December, 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:
Model Year: VIN Breakpoint
Engine: Transmission:
from to from to
Chevrolet Corvette 2014 2019 — — 6.2L (LT1, LT4)
6L80 Automatic
(MYC), 8L90
Automatic (M5U)
or Manual
Involved Region or Country North America, Europe, Russia, Middle East, Japan, Thailand
Condition
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.
Page 2 December, 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 December, 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.
⇒ 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.
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 1
N/A BOLT, CR/SHF
BRG CAP
(M10X2X96)
(LT1/LT4)
11548076
10
Causal
Part
Description Part
Number
Qty
N/A BOLT, CR/SHF
BRG CAP
(M10X2X82)
(LT1/LT4)
11548075
10
N/A BOLT, CR/SHF
BRG CAP
(M8X1.25X25
HEX FLANGE)
(LT1/LT4)
11546565
10
N/A SEAL, CR/SHF
FRT OIL
(LT1/LT4)
12693255
1
N/A SEAL, CR/SHF
RR OIL (LT1/LT4) 89060436 1
N/A BEARING KIT,
CR/SHF
(LT1/LT4)
12656814
1
N/A BEARING KIT,
CONN ROD
(LT1/LT4)
12683811
1
N/A BEARING, CLU/
PILOT (Manual
Transmission
Only) (LT1/LT4)
12557583
1
N/A TNK, ENG OIL
(LT1/LT4 Dry
Sump Only Z52)
12680701
1
N/A HOSE, AUX ENG
OIL TK INL 23299434 1
Page 4 December, 2020 Bulletin No.: 19-NA-217
Causal
Part
Description Part
Number
Qty
N/A HOSE, AUX ENG
OIL TK OTLT 23299435 1
N/A BOLT, A/TRANS
FLEX PLT
(M11X1.5X19)
(LT1/LT4)
11547118
8
N/A OIL, Engine
Refer to EPC
N/A FILTER, OIL
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
Description Labor Time
4087158*
Replace Crankshaft,
Crankshaft Main Bearings
and Connecting Rod
Bearings
24.1 hrs
*This is a unique Labor Operation for bulletin use only.
Version 3
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.
December 21, 2020 – Updated some quantities in the Parts Information section.

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