Hello. Some people say that Evo 4/5/6s have open diff up front in the t case. Some people say that some of the 5s and 6s have Helical Gear Diff (torsen/worm drive) LSD, and others have open diff. Can this situation clarified by someone. How can you tell which car or t case has which diff inside if they are indeed different from car to car. Any help would be appreciated. Thank you.

 

Sorry not any real help but you may have better luck looking on lancerregister as there's a lot more talk about early evo's on that site

 

Its a bit of a luck of the draw type deal if you got a helical front diff.

So you could have a look at the code on the gearbox, a "1" at the very end indicates it came with a front LSD, however that only counts if someone hasn't changed the transfer case.

Or you could pull the driver side drive shaft and have a look down the hole for a cross pin.