Back Flush Procedure

Connect the transmission oil cooling system flush and flow test tool adapters (1) to the vehicle's transmission oil cooler supply and return lines at the transmission. See Fig 1.
Connect the black supply hose (1) to the return line, top connector of the transmission, and the clear waste hose (2) to the feed line, bottom connector of the transmission, to the vehicle cooler lines. See Fig 2. This is the reverse flow backflush direction.
Turn the main function switch to the FLUSH position. Allow the machine to operate for 30 seconds.
Turn the main function switch to the IDLE position and allow the supply vessel pressure to dissipate.

Fig 1: Connecting A/T Oil Flusher Adapters

Courtesy of GENERAL MOTORS CORP.

Fig 2: Connecting Black Supply Hose & Clear Waste Hose

Courtesy of GENERAL MOTORS CORP.