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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 284 (Automatic Transmission Servicing - ALLISON LCT 1000) >> Lubrication >> Oil Cooler Flushing & Flow Test >> Initial Flush

Initial Flush

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  1. Turn the transmission oil cooler and line flusher water supply valve (1) to the ON position and allow water to flow through the oil cooler and pipes for 10 seconds to remove any remaining transmission fluid. See Fig 1 . If water does not flow through the oil cooler and pipes, the cause of the blockage must be diagnosed and the plugged component must be repaired or replaced. Continue with the cooler flushing and flow check procedure once the blockage is corrected.
  2. Turn the transmission oil cooler and line flusher water supply valve (1) to the OFF position and clip the discharge hose (5) onto an appropriate container with a lid, to avoid splashback. See Fig 2 .
  3. Turn the transmission oil cooler and line flusher water supply valve (1) to the ON position and depress the trigger (8) to mix cooler flushing solution into the water flow. See Figure . Use the clip provided on the handle to hold the trigger (8) down. The discharge will foam vigorously when the solution is introduced into the water stream.
    NOTE: Flushing for approximately 2 minutes in each cooler line direction will result in a total of about 8-10 gallons of waste fluid. This mixture of water and flushing fluid is to be captured in an appropriate container for proper disposal.
  4. Flush the oil cooler and pipes with water and solution for 2 minutes. During this flush, attach the shop air supply of 120 psi to the flushing system feed air valve (2) located on the transmission oil cooler and line flusher for 3-5 seconds at the end of every 15-20 second interval to create a surging action.
  5. Release the trigger (8) and turn the transmission oil cooler and line flusher water supply valve (1) to the OFF position.
Fig 1: Flushing Oil Cooling System
G00056984Courtesy of GENERAL MOTORS CORP.
Fig 2: Capturing Fluid Discharge
G00056985Courtesy of GENERAL MOTORS CORP.