Information on Water or Ethylene Glycol in Transmission Fluid – 2019 and Prior GM Passenger Cars and Light Duty Trucks

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Service Bulletin Bulletin No.: 08-07-30-035D
Date: 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.
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: nelcollc@comcast.net
Web: https://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.
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.
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.

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