Bulletin No.:

Service Bulletin

Date:

08-07-30-035D
May, 2019

INFORMATION
Subject:

Information on Water or Ethylene Glycol in Transmission Fluid

Models:

2020 and Prior GM Passenger Cars and Trucks (including Chevrolet Medium Duty LCF)
Equipped with Automatic Transmission
EXCLUDES Chevrolet Silverado MD with Allison Transmission (Must go to Allison
distributor)

This Bulletin has been revised to add the 2020 Model Year, update the Models section to
include Medium Duty information and update contact information. Please discard Corporate
Bulletin Number 08-07-30-035C.

Water or ethylene glycol in automatic transmission fluid
(ATF) is harmful to internal transmission components
and will have a negative effect on reliability and
durability of these parts. Water or ethylene glycol in
ATF will also change the friction of the clutches,
frequently resulting in shudder during engagement or
gear changes, especially during torque converter clutch
engagement.
Indications of water in the ATF may include:
• ATF blowing out of the transmission vent tube.
• ATF may appear cloudy or, in cases of extreme
contamination, have the appearance of a
strawberry milkshake.
• Visible water in the oil pan.
• A milky white substance inside the pan area.
• Spacer plate gaskets that appear to be glued to
the valve body face or case.
• Spacer plate gaskets that appear to be swollen or
wrinkled in areas where they are not compressed.
• Rust on internal transmission iron/steel
components.

Copyright 2019 General Motors LLC. All Rights Reserved.

If water in the ATF has been found and the source of
the water entry has not been identified, or if a leaking
in-radiator transmission oil cooler is suspected (with no
evidence of cross-contamination in the coolant
recovery reservoir), a simple and quick test kit is
available that detects the presence of ethylene glycol in
ATF. The “Gly-Tek” test kit, available from the Nelco
Company, should be obtained and the ATF tested to
make an accurate decision on the need for radiator
replacement. This can help to prevent customer
comebacks if the in-radiator transmission oil cooler is
leaking and reduce repair expenses by avoiding
radiator replacement if the cooler is not leaking. These
test kits can be obtained from:
Nelco Company
1047 McKnight Rd South
Saint Paul, MN, 55119
Phone: 651-738-2014
Fax: 651-738-9447
E-mail: [email protected]
Web: http://www.gly-tek.com
Test kits can be ordered by phone or through the
website listed above. Orders are shipped standard
delivery time but can be shipped on a next day delivery
basis for an extra charge. One test kit will complete 10
individual fluid sample tests. For vehicles repaired
under warranty, the cost of the complete test kit plus
shipping charges should be divided by 10 and
submitted on the warranty claim as a net item.

Page 2

May, 2019

The transmission should be repaired or replaced based
on the normal cost comparison procedure.
Important: If water or coolant is found in the
transmission, the following components MUST be
replaced.
• Replace all of the rubber-type seals.
• Replace all of the composition-faced clutch plates
and/or bands.
• Replace all of the nylon parts.
• Replace the torque converter.
• Thoroughly clean and rebuild the transmission,
using new gaskets and oil filter.

Bulletin No.: 08-07-30-035D

Important: The following steps must be completed
when repairing or replacing.
• Flush and flow check the transmission oil cooler
using J 45096. Refer to the latest version of
Corporate Bulletin Number 02-07-30-052 –
Automatic Transmission Oil Cooler Flush and
Flow Test Essential Tool J 45096 TransFlow.
• Thoroughly inspect the engine cooling system and
hoses and clean/repair as necessary.

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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