Automatic Transmission Oil Cooler Flushing and Flow Test: Notes

GM studies indicate that plugged or restricted transmission oil coolers and pipes cause insufficient transmission lubrication and elevated operating temperatures which can lead to premature transmission wear-out. Many repeat repair cases could have been prevented by following published procedures for transmission oil cooler flushing and flow checking. This procedure includes flow checking and flushing the auxiliary transmission oil cooler, if equipped.

Important:  Use the J 35944-A  or equivalent to flush the transmission oil cooler and the oil cooler pipes whenever the transaxle is removed for the following repairs:

• Torque converter
• Oil pump
• Oil pump drive shaft
• Drive sprocket support
• Transaxle overhaul complete
• Transaxle assembly replacement

Important:  Use the J 35944-A  or equivalent to flush the transmission oil cooler and the oil cooler pipes whenever the transmission is removed for the following repairs:

• Torque converter
• Oil pump
• Turbine shaft
• Transmission overhaul complete
• Transmission assembly replacement

Only GM Goodwrench DEXRON®III automatic transmission fluid should be used when doing a repair on a GM transmission.

Time allowance for performing the cooler flow checking and flushing procedure has been included in the appropriate labor time guide operations since the 1987 model year. The service procedure steps for oil cooler flushing are as follows: