10-07-30-001D

File in Section:
Service Bulletin
07 - Transmission/Transaxle
Bulletin No.:
10-07-30-001D
Date:
February, 2013
TECHNICAL
Subject:
Fluid/Oil Leak During Cold Weather from Transmission Vent
Models:
2001-2013 Chevrolet Silverado 2500HD-3500HD Series
2001-2013 GMC Sierra 2500HD-3500HD Series
Equipped with Allison® LCT 1000 Automatic Transmission (RPOs M74, MW7)
This bulletin is being revised to add the 2013 model year, update the Important statement and
add a Note. Please discard Corporate Bulletin Number 10-07-30-001C
(Section 07 – Transmission/Transaxle).
Condition
Some customers may comment on a small red fluid/oil
leak during cold weather. Upon further investigation,
the technician may find a small fluid leak in the area at
the back of the transmission by the vent.
Cause
This condition may be caused by fluid being discharged
out the transmission vent due to a low transmission
fluid fill. During extreme cold weather, (approximately
-25°C (-15°F or colder), low fluid fill can cause the
transmission pump to ingest air which can aerate the
fluid and push some fluid out the vent.
Correction
On 2001 through 2013 models, verify the transmission
is full of fluid. Follow the SI fluid checking procedure to
PROPERLY check the transmission fluid level using the
Hot Check Procedure.
Important: Ensure that the fluid level is at the top of
the HOT band when the transmission fluid temperature
is 79°C (175°F). Refer to SI Document ID# 2408059 for
the proper fluid level checking procedure.
Note: The fluid level on the indicator may be higher on
one side than the other. The lower reading should be
considered the actual fluid level. The higher fluid level
on the indicator should be considered splash.
1377427
Note: Only on 2001-2004 models, replace the
transmission fluid indicator (dipstick) with a new vented
indicator, P/N 15794381.
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.
Copyright 2013 General Motors LLC. All Rights Reserved.
WE SUPPORT VOLUNTARY
TECHNICIAN
CERTIFICATION