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      05-03-2013, 10:13 AM   #50
Majin Buu

Drives: M3
Join Date: Apr 2013
Location: Canada

iTrader: (0)

Flushing the transmission and cycling the pump is really easy. You don't need any fancy special tools. The pump has a connector with a wiring harness plugged into it. This harness has a brown wire and a red wire. The brown wire is connected to the ground. The red wire is connected to the +ve terminal of the battery via the car's computer. When the oil gets hot, the computer completes the circuit to activate the pump.

The dealer cycles the pump by completing this circuit via their scan tool. But you can MacGyver your way around this problem. All you have to do is directly connect the +ve battery terminal to the red wire bypassing the car's computer control. All I did was unplug the connector, and take it apart. I then piggybacked a small old wire onto the red wire and reassembled the connector and plugged it back in. The other end of my piggybacked wire was loose and hanging out of the connector. Then I got booster cables, connected one end to the +ve terminal under the hood, and touched the other end of that cable onto the exposed end of my piggyback.

After you drain the transmission oil, you leave the drainplug off and activate the pump for 30 seconds. This drains the oil in the cooler and lines. Then tighten the drain plug and fill the gearbox with 2 L of oil. Close the fill plug and cycle the pump again for 30 seconds to refill the cooler with new oil. Then open the fill plug and top off the oil till it flows out of the hole and tighten the fill plug. And that's it.

Using this method I was able to change about 2.5 L of oil, which I believe is a complete flush.