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You might also be interested in the wiki article "Transfer box conversion to Rock Lobster".

Тhis wiki article is an unfinished copy of the original old BigJimny PDF guide.
All the text has been copied with minimal adjustments, but all the pictures are missing.
Someone needs to add the original pictures to make it a complete copy.

Introduction

The Jimny transfer box (both manual and electronic) are not popular with off road enthusiasts. In both variations the main drive is achieved through the use of a chain and in the electronic version the added complexity of an electronic motor and its controls make it more unreliable. The chain can wear and slip, particularly with those ratio modification kits that change the gearing around the chain. Therefore many people like to change to a gear only driven transfer box, the common (only?) solution is one from an SJ series off-roader.

Despite the similarities between an SJ and Jimny, it is not a straight swap, you require some form of mounting kit. Depending on the kit you use, you will have to change the propshafts as well because the overall mounting position of the box will change. A number of mounting solutions exist:

• DG Tuning
• Rob Storr at RS Engineering
• Rockwatt Engineering

All of them make mounting kits at various prices. It is also not too difficult to construct your own if you have the ability to weld well. I chose to use the kit from The Off-Road Armory (ORA), this has now been discontinued so although this guide shows the steps in principle, you can no longer purchase this kit.

What is needed

The Off-Road Armory kit comes with a set of mounting brackets, replacement rubber mounts and the Speedo converter. However some other parts are necessary, depending on what you are attempting to do.

In order to fit the box you will need an SJ min-prop (the small prop-shaft between the Gearbox and Transfer Box), an SJ Front Prop-shaft and a Jimny Front Prop-shaft. You will also need some SJ Flanges. The Jimny’s original Flanges are similar to the very last Suzuki Samurai 4x4s. Therefore, if your really lucky, using the Flanges and Props from a late Samurai will mean you can bolt it all on. Of course, these parts are like “Hens Teeth” so in all likelihood you will have to mix and match Props and Flanges to suit. The other point to note is that an extended Flange is required for the output shaft, which you will not have if you have been working with SJ Transfer Boxes which have the Drum Brake fitted to the case. You will have to find a proper SJ Output Flange as the shorter Input or Front Flanges cannot be used on the rear. There are pictures in the text showing the issues, but make sure you have collected all the parts before you start.

Finally, you will need nuts and bolts to affix the Prop-shafts, this may seem obvious but the Flanges on the Jimny are threaded whilst the SJ Flanges are not. Therefore you will not have suitable nuts after dismantling the Jimny case and the bolts are too short as they only have to reach the threads in the Jimny Flanges but they have to go right through the SJ Flanges to bolt up.

The work

• First you have to get ORA kit. The picture below shows the kit as shipped. In the kit you get the Speedo adaptor, the mounts and bolts and washers to assemble it all. Not shown in this picture are the replacement mounts which are included in the kit but came separately in my early version.

File:FIGURE 01

FIGURE 01 - ORA kit

• The picture below shows the mounts in greater detail. My mounts came in plain steel but later versions should be power coated.

File:FIGURE 02

FIGURE 02 - ORA mounts

• The picture below shows the Speedo kit.

File:FIGURE 03

FIGURE 03 - ORA speedo kit

• The first stage is to assemble the Speedo kit onto the SJ Transfer Box. You will have to get a set of SJ Flanges to match the prop-shafts you have, if you cannot get the correct ones then you will have some drilling to do. The picture below shows SJ Flanges with the largest on the left (You WANT these!!) to the smallest on the right (You want to AVOID these).

File:FIGURE 04

FIGURE 04 - SJ flanges

• The Speedo kit fits on the output Flange, which needs to be a proper, extended output flange (which you may not have if you have used SJ Transfer Boxes fitted with the handbrake drum). The picture below shows what you need.

File:FIGURE 05

FIGURE 05 - The Wrong (left) and the Correct (right) Flange

• Now you need to remove the cup on the end of the Flange, this is a friction fit and can be tapped off with a hammer.

File:FIGURE 06

FIGURE 06 - Flange with the cup removed

• Now you need to clean up the stem of the flange. The oil seal is going to fit over this and ideally the oil seal should sit on a machined surface. The Flange is rough cast and does not make a good Oil Seal surface, you should clean it up the best you can to smooth the surface as much as possible. Then push the Oil Seal onto the Flange as shown below.

File:FIGURE 07

FIGURE 07 - oil seal fitted

• Now the Speedo gear needs to be fitted. This friction fit over the end of the flange. ORA recommends that this is pressed on using a press, you can use a Vice as it is not too hard. I put the Flange in the freezer and the gear in the oven for a short while and then the gear just dropped into place.

File:FIGURE 08

FIGURE 08 - assembled flange

• The picture below shows how it fits onto the Transfer box, but this is only for demonstration purposes. In reality you need to fit the Speedo Sensor case FIRST!

File:FIGURE 09

FIGURE 09 - example fitting

• You need to fit the case and then fit the Flange inside. Grease the oil seal with Copper Grease and push the assembly together. You may need to use a flat piece of metal to push the Oil Seal into place.

File:FIGURE 10

FIGURE 10 - The Speedo Sensor case in position

• You should now end up with.....

File:FIGURE 11

FIGURE 11 - Finished SJ case alongside the old Jimny Case

• Now it needs to be fitted to Jimny. Attach the correct Flanges for the Prop-shaft sizes you have. Remember you need an SJ Mini-prop and SJ Front Prop (to be fitted on the Jimny rear). The original Jimny Front Prop stays in place.

• The kit comes with replacement bushes made from Polybush material. These simply replace the existing Suzuki bushes and being slightly thinner they lower the Transfer Box slightly to help with the clearance under the transmission tunnel and to stop the Mini-prop hitting the Gearbox remote mechanism.

File:FIGURE 12

FIGURE 12 - polybush mount

• Now before you all write in, I know the nut and bolt are better off the other way around so that the nut and end of the bolt do not protrude down below the car. I swapped it over after the picture was taken.

• Now you need to fit the Transfer Stick. As you can see from the picture below the position of the SJ Transfer Box means that, un-modified, the stick is jammed against the transmission tunnel (and this is with the stick in the fully “back” position–it needs to shift forward from here!). I found this the hardest bit as it needs a lot of heat to bend it, its really not possible to cold bend it and no-one has gas nowadays, only MIG, so its hard to find someone with the right tools.

File:FIGURE 13

FIGURE 13 - un-modified lever

• However I did find someone eventually. The stick needs to be rotated and bent back. Here is the finished item, in exactly the same ratio (4WD High) as in the picture above.

File:FIGURE 14

FIGURE 14 - lever bent into position

• Here is a further picture showing an original level on the right and a modified one on the left. Both lever ends are in exactly the same, correct, position showing how much of a bend is needed.

File:FIGURE 15

FIGURE 15 - Transfer Lever showing "rotation" and bend

• So now we are on the home run. You need to replace the rubber boots on the lever and bolt up the propshafts. In my case I could only get the medium size SJ Flanges and Prop. Therefore I needed to drill the

rear Diff Flange to take the prop. This involved clamping the prop to the flange and drilling through.

File:FIGURE 16

FIGURE 16 - Flange clamped for drilling

• Remember to fill it with oil and connected up the 4WD switch and Speedo sensor. Now go and enjoy yourself!!

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Page last edited on 15/01/2018 by user Mlines