Grant, all Evo I-III rear diffs are mechanical LSD except for the Evo I GSR which had the viscous rear LSD.
Here's the rundown on what to do depending on what ratios you want to run with.
Keeping the GSR Lancer 3.545 rear diff ratio
If you're going to keep your GSR gearbox, then yes, put an Evo mechanical LSD centre into a GSR rear diff housing. Go to a gearbox and diff shop, hand over your complete GSR diff housing and the EVO mech LSD, and ask them to put the LSD centre into it for you and to set the tooth alignment and backlash and also to fit new bearings and seals if required. Should cost a couple hundred bux maximum. The existing GSR crownwheel and pinion inside the housing determines the GSR 3.545 rear diff ratio, not the Evo LSD. Once done = rear diff is now GSR ratio with a mech LSD B)
Gearbox options using GSR front diff ratio to suit the above rear diff
a ) Keep your existing GSR open front diff gearbox and transfer case as they are. It'll be fine to use with the diff as per described above.
b ) Keep your existing GSR open front diff gearbox and transfer case but fit an aftermarket mech LSD front diff (Kaaz, Ralliart, Cusco, whatever) in it using your existing GSR front diff crownwheel and pinion (C&P).
c ) Get any EVO I-III viscous LSD gearbox, remove the Evo's front LSD C&P and fit a GSR 58-tooth viscous LSD C&P onto the EVO's viscous LSD centre. Big Problem: GSR 58 tooth front viscous LSD crownwheels are rare to find! I have only ever come across one of them and its in my garage waiting to be fitted to an EVO viscous LSD centre! :lol:
d ) Get a non LSD EVO gearbox, buy an aftermarket mechanical LSD (Kaaz, Ralliart, Cusco whatever), then fit a non LSD normal GSR 58-tooth C&P onto the aftermarket mech LSD and chuck it into the EVO box. Basically nearly all GSR boxes are open diff so you can take their C&P off and fit them to any W5M33 aftermarket mech LSD. You will however require 8 x new MD952231 LSD bolts as they are longer than normal open diff bolts. The extra length of the bolts is to go through the thread of both the LSD cover and LSD body (important!). The end result will be EVO gearbox with aftermarket front mech LSD and a GSR front diff ratio... to suit your new rear diff
Alternatively, if you want to go with the full EVO 3.909 rear diff ratio, get EVO running gear:
Buy an EVO I-II gearbox with front viscous LSD and ensure you get a driver's side LSD CV cup with it! Very important. It's different to a normal CV cup.
Use your existing GSR transfer case or get an EVO I-II transfer case.
Use a complete rear EVO I-III mech rear LSD diff centre and housing.
Note: If using an EVO III gearbox ensure you get the matching EVO III transfer case! They are a matched pair to suit the EVO rear diffs.
Hope this helps.
PS: Dont stress, it upsets the penguins
