I recently tried to order a new ACD pump (specifically "Hydraulic unit, diff control", part no. 3520A077 or MR580057) from Savannah Mitsubishi and discovered that it is now discontinued. Attempts to order this part from other Mitsubishi dealerships confirmed the same thing. There are probably still a few new units floating around out there but the stock will continue to become more limited as time goes on. I'm not sure whether JDM dealerships can obtain the part but I'd be surprised if they can when US ones cannot.

I realize there are rebuild kits for this pump but as far as I know there are no aftermarket replacements. I would argue this is a pretty disappointing development for our cars given how frequently these pumps fail. The rebuild kit may add some life to the unit but I suspect in many cases these will eventually also fail.

My '05 Evo 8 is on its second ACD pump which has now failed. The first one failed because a shop tech didn't bleed it after swapping my clutch. The second one was a used unit from Ebay and it has failed naturally. I suspect a similar fate may come for other ebay units.

Without a functioning ACD pump, our cars revert to an open center differential and lose their all wheel drive. This was a big part of the appeal of the Evo for me personally. If yours still has its pump working, consider yourself very lucky. You never know when its day will come.

 

They lose AWD, so non ACD cars have no AWD ?

 

For Evos that is correct. Without a hydraulic system to partially close the diff, it's just an open diff. It's not going to do better at selective power transfer than just a transfer case/4WD would.

 

It still has AWD if the ACD is out. I suggest doing some research on the ACD in this forum.

 

I thought so, his post had me scratching my head ...
Thanks for clarifying.

 

You can use EUDM/JDM pumps, if available, and also evo X pumps will work with minimal work..

 

good lawd.... ...

Non ACD cars are AWD...
lets just clarify that.

 

hmmm.... what minimal work do you have to do on an X pump?

 

Without hydraulic pressure, the center diff defaults to open differential

 

Still doesn't mean it's not AWD. Tons of AWD cars out there with open diffs. The 03-04 Evo's had open front diffs. Golf R, A3,S3, RS3, TT,TTS,TTRS have open diffs, Focus RS, bunch of Subarus, etc.

 

I'm not sure what you mean. The cars you listed all have some kind of mechanism to either move torque to one axle in certain cases or to lock the front and rear axles (close diff) together. If you removed or disconnected those mechanisms then yes, those cars wouldn't be AWD anymore. Similarly if you remove the ACD or ACD pump from an Evo it is not AWD anymore. There are plenty of examples of 4WD vehicles with front and rear diffs but no center diff or effectively an open center diff.

 

I'm sorry, you are wrong. Again, I suggest reading up on the ACD and Evo awd system. Plenty of resources on this forum.

 

I think you have two different "AWD" systems confused for being all the same. I'll give you an example, a 2wd truck does not become no-wheel-drive just because it has an open differential. As soon as one tire looses traction, that wheel keeps spinning so it becomes one-wheel-drive.

AWD systems you are talking about only send power to the front wheels, when traction is lost, power is sent to the rear.

I would recommend you get on youtube and start watching different types of AWD systems. They are NOT all the same.

 

I think you might be getting confused. I never suggested otherwise. I even called this out here.

Will all 4 tires spin? Sure. But you no longer have the ability to lock up the differential, which is part of what makes an Evo an Evo. Whether you want to call an open diff AWD or not is up to you. It will drastically change how the car drives though.

 

ok bro