So I did this a long time ago and people keep asking if I would do a write up on how I did it. If you have knowledge of setting up a ring and pinion it should be straight forward. If not you may want to have someone else do it. I was lucky and I was able to reuse all of the factory shims and my pattern was perfect. I recently took everything back apart as I learned the Evo diffs were assembled wrong from the factory for all USDM cars. If you plan to install this diff I would highly recommend re-stacking the plates before installation. To do the swap you need the diff from and Evo 3 or 7-9. I don't know if the rest are the same or not. I am using the diff from a 9. You also need the inner cv joints from said diff. I started with a 4 bolt rear so I don't know if the 3 bolt will work or not. I think the axles are assembled differently.

1st remove evo diff from carrier.



Take Diff apart and see its assembled wrong.



I then cleaned all of the parts and prepared for assembly.



All stacked in the proper order. I dipped all of the plates and disc in good gear oil during assembly so they wouldn't be dry for the first couple of turns.



Install the ring gear from your 4 bolt dsm diff using red thread locker.


Install it in your 4 bolt rear carrier and torque all of your fasteners.



Check your backlash and pattern and if good install the rear cover, mustache bar and fill with your favorite gear oil(After you put the axles in).

Now you need to remove the inner cv joints from your 4 bolt axles by gently prying the tabs open on the clamps. You can then slide the joint off and remove the clip holding the tripod joint on. Do the same for the Evo axles. Install all of the Evo axle parts on to your 4 bolt shafts and fill with the proper grease. Fold the clamps back down tight on the boots and install axles into the diff.

You are now ready to enjoy some awesome on throttle over-steer. This is one of the best mods I have done on the car for handling. Hope you enjoy.

Yes, basically that is it. I install the joints onto the axle before I install them but you have the general idea. You may need shims if your pattern or backlash is incorrect. I was lucky and mine was correct. You will also want to inspect the bearings and what not. My diff only had 14k on it so it was good. I know the Evo diffs have a problem with the side cover distorting if your making big power so you should inspect the bearing on that side of the diff carefully. I plan on installing the upgraded TRE side cover eventually with the upgraded pinion spacer but it wasn't in the budget for this year. I would actually like to do the 12 plate upgrade but haven't figured out what all that requires. I don't want to pay someone else $1000.00 to do it for me but it may eventually come to that. Also I used Amsoil 80w90 gear oil and have had no chattering noise from the diff and it locks nicely at the auto-x on Hoosier tires. I can pretty much drift the car with full on power through a sweeper in 2nd gear.

Rear diff mechanical/plate/clutch type part numbers:

"Differential Kit, RR Limited Slip"
-----------------------------------
E38A VR4 RS MB664374 (1.0 Way LSD)
CD9A Evo 1 MB664374 (1.0 Way LSD)
CE9A Evo 2 MR166619 (1.5 Way LSD)
CE9A Evo 3 MR166619 (1.5 Way LSD)
CN9A Evo 4 MR166619 (1.5 Way LSD)
CP9A Evo 5 MR166619 (1.5 Way LSD)
CP9A Evo 6 MR166619 (1.5 Way LSD)
CP9A Evo 6.5 MR166619 (1.5 Way LSD)
CT9A Evo 7 MR166619 (1.5 Way LSD)
CT9A Evo 8 MR166619 (1.5 Way LSD)
CT9A Evo 8MR MR166619 (1.5 Way LSD)
CT9A Evo 9 MR166619 (1.5 Way LSD)
CT9W Evo Wagon MR166619 (1.5 Way LSD)
CZ4A Evo 10 MR166619 (1.5 Way LSD)

AYC and Viscous LSDs are available on (almost) all models but have been excluded. AFAIK all US market Evo's up to and including the Evo 9 have mechanical rear diffs.

VR4 (those with 4 bolt axles) and Evo 1, 2 & 3 LSDs accept 4 bolt axles without modification. However, mechanical LSDs require equal length inner CV shafts to operate: Viscous LSD inner CV shafts will not fit or work. The required shafts are found on 4 bolt open and 4 bolt mechanical LSD diffs.

If 4 bolt axles work with Evo 1, 2 & 3 LSDs, and the LSDs in Evo 2-10 are the same, then standard equal length 4 bolt axles should fit any Evo LSD and you step involving breaking out CV joints is not always required.