August 28, 2014 TFDarian

Service: EVO X AYC Pump Relocation

In the recent years, EVO X owners have begun experiencing a problem with their ACD/AYC pump. This pump is in charge of the center differential and yaw control. It basically controls your torque, and acts like a limited slip, on its own. The pump tries to give the best acceleration by directing power to the wheels with the most grip. So it adds power to the wheels in grip and reduces power in the wheels lacking grip. If you were to choose to increase the AYC settings, you would notice more power in the rear, and vice versa if you decrease the settings.

However, cars located in climates that experience harsh winters, like the US Midwest and Europe, have had this pump fail on them. The pump rusts away from the inside and holes emerge in the casting of the unit. Weather and corrosion seem to contribute to the problem, but a concrete cause is not yet found. There are EVO X owners all over the world who do not experience this weather, and the problem for them is not as frequent.

The problem arises when it comes to replace the part. Mitsubishi does not cover this under the warranty, and the part costs over $2000 new. This pump is located in the back under the passenger side trunk. TFWorks has devised a solution by relocating a working pump into the trunk. The purpose of this is to hopefully prolong the life of the pumps. Since the inside of the car does not experience the same kind of exposure to elements as the outside, this solution seems to be working.

Below are some pictures of the pump and solution.

Here we have the old, rusted unit.


The corrosion has gotten inside of the seal and caused rust to form inside the pump.

Between the casting and the solenoid, there is a buildup of dried fluid that made itself out of the pump due to a hole in the casting.

Here is the solution. We mounted a brand new pump inside of the trunk. We believe that this will prolong the life of the pump.

In order for this install to look proper and legitimate, we opted to make it look factory-spec by putting under the OEM carpet.

It’s as if it wasn’t even there!

If you are interested in having us relocate your ACD/AYC, please contact us.