The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

  • Update Your Password Today!

    We have implemented tools to identify member accounts using insecure passwords and will be locking those accounts until their passwords are updated. Don't get locked out of your account - update your password today, and ensure your account has a valid email address on file. Read more here...
Please Support Morrison Fabrications
Please Support Rix Racing

EVO Rear LSD in a 1G/2G housing

Status
Not open for further replies.
First and foremost, all the USDM Evos come with the rear differential configured to provide far less lockup than the diff is capable of. This, in my opinion, is because US drivers are sissies and dont want to hear the diff chatter when making low speed turns, and also need a car that will understeer rather than oversteer when cornering at speed. Fixing this issue by reconfiguring the diff to provide as much lockup as possible in stock form is as simple as taking the diff apart and rearranging the plates within. I would start with this and if you are unhappy with the diff, there are options for adding more plates in order to make the diff lock even more aggressively, which I will get into later on. Another thing to pay attention to is the side cover on the diff. If you remove the diff from the housing and the bearing on this side just falls off the post, you need a new side cover, the OE side cover is weak and doesnt withstand much abuse, so the solution is to purchase the HD side cover from TRE. This part is well worth the money and provides much needed insurance to prevent breaking the ring gear, which will take out the pinion and maybe even wreck the diff as well. I will include pics of the parts in question below.

The swap, and whats needed:

1. The rear differential. These are availible in ALMOST every Evo of every year produced. Keep in mind that the early Evos allegedly were availible with the viscous style rear LSD, and the later Evos were availible with the AYC option, neither of which is what you want, so you must confirm that youre getting the right diff before purchasing. The following is a list of the cars that came with the diff that we need:
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)
You will also need the proper axles for this swap. The following setups in the list below have been confirmed to work by a few DSMers who have performed the swap. I have also listed the axles that cannot be used as well.
(First, it has been confirmed that though they look like they will work, the shorter, 1G 4 bolt and 2G shorter LSD axles will not work safely with the EVO diff, the splined section of the inboard cups are too short, the locking ring wont engage in the diff and the splines will shear off in a catastrophic manner- you will hate it.)
(Second, I tried fitting 3 bolt non LSD axles into the EVO diff, and they dont even come close to fitting into the diff properly, theyre just too small. The 3 bolt LSD axles also cannot be used as these cannot even be fitted with the EVO inner cups)
The following axle setups will work with the EVO rear LSD:
1.1G, 4 bolt NON LSD axles (1G car ONLY. These are said to exist, I however have never seen a 4 Bolt non lsd rear)
2.2G NON LSD axles (2G car ONLY)
3. Hybrid 1G, 4 bolt LSD/ EVO rear axles: EVO rear inboard (the part that is attached to the CV that goes into the diff itself) cups, swapped onto 1G, 4 bolt LSD axles. Whats needed? Two 4 bolt LSD axles, a left, a right, or two rights or two lefts, whatever you can get, it doesnt matter because youre putting an inner EVO cup onto these. The bearing tripod from the EVO axles are dimensionally identical to the ones on the 1G 4 bolt axles as well, though it may still be a good idea to swap the EVO bearing tripods onto the 1G axles since the rollers are bed to the cups they came with. (In theory)
4. Hybrid 2G LSD/ EVO rear axles: I am aware that one or two 2G guys have done this. It is the same as the 1G swap, however, Im not sure if you have to swap the bearing tripods from the EVO axles onto the 2G axles in this case or if the 2G tripod is the same as that of the EVO. (If anyone can confirm whether or not the 2G bearing tripods are dimensionally identical to those of the EVO, please PM me so I can edit this info into this writeup)




On to the rear diff. You will need to remove the EVO diff from its housing, if you purchased the diff in the housing. Begin by removing the cover plate. After you remove the bolts holding the cover to the housing, look at the top and bottom corners of the housing at the flange, and youll notice a hole. This is there so that you can insert a punch and tap with a hammer to separate the cover from the housing- see the picture below. Once youve removed the cover plate from the housing, remove the four bolts holding the diff in the housing. You need to carefully remove the diff, using care to be sure you keep each bearing race with its respective bearing, and also each shim with its bearing, and do the same when removing your stock diff from its housing- I used bags marked "EVO Left", "EVO Right", and "DSM Left" and "DSM Right". You will remove the ring gear from the EVO diff so that you can install your 2G ring gear (If you have a 2G) or 1G ring gear (If you have a 1G car) onto the EVO diff. This can easily be done with a 1/2" drive impact, and once the bolts are off, you can gently tap the gear loose with a soft blow hammer, or do what I did in the pic and just screw two bolts, 180* from each other partially into the gear by hand, then tap (very gently) with a hammer and the gear comes loose. Use brake cleaner to thoroughly remove the old loctite from the bolts and the threads within the gear.

You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.


Now that the ring gear is off, you can remove the four small set screws that hold the side cover to the spool. Before you do this though, look closely around where the cover meets the spool body, and you will see a line machined into the spool and cover- you will want to line these up when you reassemble the diff. The small screws are loctited in and will strip if youre not careful, so a good trick here is to put a #2 phillips screwdriver onto a screw, then hit the handle of the driver hard once or twice per screw. Now push down as hard as you can and turn the screws loose- do this evenly, dont just completely remove one screw at a time or you could potentially warp the surface of the side cover! Now that the cover plate is loose, you can carefully lift the spool off the side cover plate and you will be left with this nice stack of clutches. Stop! Note the spring plate at the top of the stack. This provides preload to the clutches on this side and it must not be flipped over when you reassemble the parts. There will also be another spring plate on the other side of the diff. Use a sharpie and mark the face of this spring "UP". Now, take all the plates from this side of the center section, (clean them if you wish) and arrange the plates per the picture below. Lube the plates with the LSD oil you will be filling the diff housing with and set this stack aside. The next portion of the stack is the center section of the diff. Use a sharpie and mark the face "UP". Now, lift the center section off- carefully, if you dont grab both sides, you can spill the cross shaft and spider gears all over the place. Grab the rest of the plates and lift them all off the cover plate, leaving the spring plate. Stop and mark the spring face that is facing upward "UP", then rearrange this side, lube the plates and place this stack back onto the coverplate, put the center section back on, then put the first stack of plates onto this and carefully put the spool back over the whole thing.

You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.


You must be logged in to view this image or video.



Once youve put the spool back on and lined up the mating marks, its time to put blue loctite onto the four little screws holding the side cover to the spool- torque these in stages evenly until youre readiy to fully tighten them. Now install the ring gear. This is to be torqued in a "star" pattern, and you need to use loctite on the bolts, however, its very important that you have the ring gear flush and square to the diff before you try torquing the bolts cause if the gear isnt square, you will force it when you tighten the bolts and can possibly damage the gear, diff housing or both. A good trick to get the gear flush and square is to get the gear where it needs to be, then take two ring gear bolts, hand tighten them til theyre snug 180* from each other, and after you get the other six bolts snugged down with loctite on them, you can remove these two bolts, apply loctite, snug them then begin final torquing the bolts in a star pattern to the FSM specifications, or 62 LB FT if youve got the TRE HD side cover.
You must be logged in to view this image or video.


Now comes the fun part. In order to install the diff properly, you must set the backlash and tooth engagement pattern as specified in the FSM, otherwise, you will have some unpleasant drivetrain noise, and you may even destroy some shite. Refer to the FSM for this info. If youre lucky however, you may be able to put the EVO diff into your DSM housing with your DSM shims or the EVO shims, and when you check the engagement pattern and backlash, itll be correct. After you torque the four bolts holding the diff in the housing, the only way to be sure if the backlash and tooth engagement pattern is correct is by following the FSM. Below are some pics of me setting up my own differential. If you do not have the tools to perform this operation, take the diff and housing to a shop that can- do not just put the diff in and assume everything is fine. My backlash was at .011, and the FSM calls for .002"- .008", so I had to reshim the diff until I ended up with .004". Also, you want to check for runout on the ring gear after everything is all bolted up. The FSM states that .002" runout is the limit- mine was at .0005"- .001".

You must be logged in to view this image or video.





So, youve got your axles, the EVO rear diff is properly installed in your DSM housing and youve got her all bolted back onto the car. What next? Fluid, of course! The factory DSM viscous coupling is a sealed unit, and therefore doesnt care what fluid is in the diff housing, you just use a good GL-5 hypoid gear oil to protect the spiders, ring and pinion, and youre good. The EVO diff however, is a clutch type, mechanical differential and the plates need the right fluid in order to function properly. The EVO uses Mitsubishi Diaqueen LSD fluid (Not to be confused with Diaqueen TRANSAXLE fluid!) from the factory here. This is as good as it gets according to some of the experienced DSM/EVO drivetrain gurus out there who are doing this stuff for a living, and if its good enough for them to put their wallet on the line by telling their EVO customers to us this fluid with the drivetrain parts theyre selling, I believe it. Another, cheaper option is Redline 75- 140 NS (No slip), which is not to be confused with their 75- 140 gear oil. This is a GL-5 oil, designed for use with clutch type mechanical LSDs, which means itll protect the ring and pinion, and it has the friction modifiers necessary to keep the clutch plates in the diff happy. The "NS" version has no friction modifiers added, so the diff will lock up as much as possible, and the regular 75- 140 has friction modifier added already. I have a Kaaz front LSD in my Laser AWD, and I use the 75- 140 NS fluid in my transmission as its a great alternative to the expensive Kaaz fluid, and its shifting and working great. Its also cheaper than Diaqueen as well. Some people have even used Redline Heavy Shockproof with friction modifier added in the rear diff with good results.
 

Attachments

  • Cover mark.jpg
    Cover mark.jpg
    26 KB · Views: 554
Last edited by a moderator:

NWHTanK

10+ Year Contributor
1,467
413
Apr 23, 2011
Odessa, Missouri
2g non lsd cups wont work to short, also if upgrading rear axles with staged dss axles they won't fit non lsd cups. Better off getting evo cups to with the evo lsd.
You must be logged in to view this image or video.
You must be logged in to view this image or video.
 
Status
Not open for further replies.
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Top