I have embarked on building my own low ratio transfer box. I have previously built two boxes, one for my SJ and one for my Jimny but both of these were 4:1 boxes built using the "Difflock" cut & shut gears. This is a frequently maligned process but the current Jimny one has served nearly 10 years so far so they cannot be too bad, however with 32" tyres it is time for something more low range.
Since I did the cut & shut one, a variety of aftermarket gearsets have appeared that provide a "drop in" solution with pre-cut gears. There are a variety available from cheap Chinese versions through to Japanese manufactured ones made in the original factory.
I went for the Trail-Gear 6.5:1 set as it represents a mid priced solution that has been on sale in the USA for a number of years. This should bring back the gearing quite nicely on the road whilst providing a very low gearing off-road.
Also needed is a Suzuki SJ transfer box, either a 410 or 413 will do (except for the very early 410 versions which are useless). See the section in the Wiki - HERE - which tells how to identify the correct box. Late 413 boxes are particularly good as they have the same larger flanges that the Jimny has, however it is straight forward to drill the old ones if necessary.
If you are doing this from scratch you will also need mounting arms, propshafts and a speedo adaptor to fit it to a Suzuki Jimny. Of course, I already have those parts on my as it has a 4.1:1 Transfer box already fitted.
So the build begins......BigJimny's Transfer box.