Ring & Pignon replacement
(Off course replace front and back)

A popular and affordable mod to get a shorter gearing for 413 or Samurai is replacing the Ring and Pignon with Vitara's Ring and Pignon. For a 410 one could consider swapping Ring and Pignon from an LJ80.
The numbers............
LJ80 SJ 410 SJ413 Samurai Vitara
4.556 4.111 3.909 3.727 5.125

Nice set of numbers but, what does it mean?
It really is very simple. The number you see is the gearing at the diff. This means, the amount of rotations the driveshaft must make to turn the wheel once.
The higher that number the shorter the gear and thus the power (torque). Your engine will not die on you after mounting (too) big wheels.
The sollution in running bigger tyre's is not in Horsepower but in gearing (I run 33X12.50 with the standard 410 engine of 970cc)

Because of the fact I was planning to do this mod I've mounted 413 axles under my 410. The 410 axlehousing of the diff is too small for throwing in Vitara R&P. LJ 80 does fit but I was told it is not as strong as the Vitara and the difference was too small to my likings. The endgearing difference between Samurai and Vitara is a nice 30% shorter..........

How does it work?
First you get a FRONT DIFFERENTIAL from a Vitara. The housing may be trashed as well as the differential itself. You only need a part of the diff and the Ring and Pignon. The advantage of knowing this is it will give you an angle on negotiating the price at the scrapyard
Part of the differential is used to make a ring to make everything fit.

First you take out your own diff. You will have to take off the wheels, brakes, axles, driveshaft and differentialhousing of course and I am not going to tell you how. If you don't know basic stuff like that, you have no business replacing your Ring and Pignon!!!!!!

I would like to give you a usefull tip, before taking of the wheels, first take of the driveshaft and losen the nutt in the flange. This one is tightend really well (undo the dent in the nut)

After taking out the bearingadjusters and caps, you can lift your differential with the Ring completely. 

The 413/Samurai Diff has 4 solargears and Vitara's got only 2. 4 is stronger than 2 so we keep our own diff!. The Ring can be taken off.

  

Because you allready losened the nut from the flange and the diff is out, you can easily lift out the Pignon. Immediatly replacing it with the Vitara Pignon. Use your own 413/Samurai housing because it has an oilpath towards the front bearing (vitara doesn't) Remount the flange with a "preload" of 2.8~3.2Kg. This means the bearing should be tightend that much that it would take that amount of force to turn it. I just tightend it that much that there was no slack and it turned easily, I think it's okay

The big trick! In order to get shorter gearing the Ring has MORE teath and the pignon LESS ofcourse. The result; the pignon is thinner than the original which means the Ring should be mounted more to the middle. That is something that can't be done by adjusting the bearings on the side, therefor you need a ring.Take the lid of the Vitara diff and have a machineshop take out the hart with a lathe. Now you have a beautifull ring.

   
 
 

Put the ring on the diff and attach the Ring to them. I recommend using the 9Kg of specified torque and maybe even locktite. Some of my bolts loosened by themselves and a couple of them broke. One of which came out the backside of my axle!!!!
(Pic's of the damage on the end of this page
)

After attaching the Ring to the diff you can place it back in the housing. By turning the bearing adjusters you can tighten and losen the bearings as well as positioning the Ring towards the pignon. Reading the manual this seems to be a whole science of it's own and I'm sure it all makes a difference. With my diff I've adjusted everything to run smoothly without slack or "hard parts" using the "feeling-tool" because I don't have the fancy equipment like measuringclocks.........

Leaves us just to put some good oilresistant kit on it and put it back in the axlehousing Put back the axles, brakes and wheels and the driveshaft. The rig is blasting off like never before
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