Contact Us

The Suzuki Samurai has been becoming increasingly more popular with the serious rock crawling crowd. It's small size and light weight, with a few strategic modifications, give it superlative balance and agility in extreme rock crawling environments.

Basically, the formula has been to install a lift, 31 or 33 inch tires, and set up the axles with 4.56 or 4.88 gears along with maybe a locker or two. The next step was 4.10 or even 4.88 gears to go in the transfer case. All this could be done with relatively low bucks, which, coupled with the extremely low base cost of a used Sammy, makes for a hell of an economy rock crawler.


The Klune-V adapter and coupling flange are bolted to the Samurai transfer case.

Serious Limitations

There were those who wanted to go further. The stock Suzuki motor really has plenty of power for truck rock crawling, but you gotta get those gears WAY down there. Figure you have a 2.5 to one first gear in the trans, and even if you have the 4.88 gears in the T-case, with 4.88 axles: your crawl ratio is:

2.5 x 4.88 x 4.88 = 59.54

About 56 to one is certainly much lower than a stock Samurai. But these gears just aren't deep enough! Not even by half. Not if you want to effortlessly run with the big dogs. You would still need to do a lot of clutch slipping (Oh, the smell of burnt clutch in the morning…). And you'll be giving the starter a mean
workout. The Sammy 4-banger needs to spin a few RPM to make any power. It doesn't have enough torque to simply idle through things without a heck of a lot of gear multiplication.

The Samurai tunnel area must be cut open to allow clearance to fit the underdrive. In the picture on the right you can see a top view of how the unit fits into the vehicle.


	Underdrive/transfer case assembly being re-installed into vehicle. Have two people handy: This operation is best done with a bit of patience to avoid damaged knuckles.

If you could get a Sammy down in the 175-to-one or maybe even the 250-to-one range you would see some truly dramatic capability increase. This would make a truly world class crawler. It would smoothly crawl almost anywhere. It would even have enough torque to simply idle up a waterfall. It would be able to, in extra slo-mo, follow a tricky line in some super-technical rock obstacle.

Underside view of unit installed in vehicle. The transfer case mounts shown are stock Samurai. It may be advisable to beef these up some: They may not hold up under serious wheelin’.

Klune-V has taken its trail-proven Extreme Underdrive and adopted it to the Samurai. These units, originally built for V8s, are way overkill.

An Extreme Underdrive must be installed between the transmission and transfer case of the vehicle. Since the Suzuki Samurai uses a divorced transfer case, it was deemed optimum to try to fit the unit in place in front of the transfer case, where the factory intermediate drive shaft goes. In this manner, the install could be done without any drive shaft cutting or modifications developed which directly mounts the underdrive to the front of the transfer case. A flange was designed to couple the torque from the crawl box to stock Samurai T-case input flange. This flange accepts the output shaft of the Klune-V.

Originally, the car had a short intermediate drive shaft running between the transmission and transfer case. What gets done here is to disassemble this shaft, and couple its original slip-yoke (from the transmission end of the shaft) directly to its flange, omittting the shaft part. This then slips into the rear of the tranny in the usual manner, and will bolt to a flange on the input side of the Klune-V.

The factory T-case mounting brackets are used to support the transfer case. Now, there is a good chunk of additional weight hanging off the front of the T-case. And since we had only a single U-joint in the intermediate shaft now, we needed to hold the underdrive and the transmission tightly in line with one another so the short coupling shaft would not be under any bind.

This photo shows how Klune’s replacement tranny mount is supported by the stock crossmember. Arrow indicates the shims used in the mounting process. This allows precision adjustment of height, allowing the transmission to be aligned properly with the Underdrive.

The design…

An aluminum adapter was developed which directly mounts the underdrive to the front of the transfer case. A flange was designed to couple the torque from the crawl box to the stock Samurai T-case input flange. This flange accepts the output shaft of the Klune-V.

Now, there is a good chunk of additional weight hanging off the front of the T-case. And since we had only a single U-joint in the intermediate shaft now, we needed to hold the underdrive and the transmission tightly in line with one another so the short coupling shaft would not be under any bind.

A steel bracket was designed which supports the front of the underdrive, as well as the rear of the tranny (the original cast mount from the rear of the tranny is not used).This bracket is supported by the factory rubber transmission mount bolted to the original location on the factory cross member.

Since the Underdrive is larger than the space in the body that the intermediate shaft went, some metal has to be trimmed from the tunnel area of the floor, near the stock shifter location.

Klune supplies some formed sheet metal panels which cover this opening. They bulge enough to leave room for the crawl box. The formed metal covers mentioned above are screwed in place. We use RTV sealant between the panels and the body to provide a rattle-free, dust and leak free seal. The shift boots are screwed on and the shifter balls twirled in place. With the panels in place and a little spray paint, it is quite a clean looking install. Put some oil in the gear boxes, and bolt the seats back in, and we were ready to go for a spin.


The Samurai tunnel area must be cut open to allow clearance to fit the underdrive. In the picture on the right you can see a top view of how the unit fits into the vehicle.


This photo shows the formed metal tunnel replacement panels Klune-V supplies. Note the additional shifter coming up in front of the t-case shifter. That is the Klune-V Extreme Underdrive shift lever. It operates with a tight race-car feel, shifting the Underdrive in or out.	Klune-V supplies hydroformed metal body panels, formed to exactly replace the missing tunnel sections, made to clear the Underdrive. This is what it looks like from the interior once the unit has been installed. This metal work can then be covered with carpet or with a spray-on truck bed lining for a dressy, factory finished appearance.

Steve Kramer, in his newly Klune-V equipped Samurai, drives up to the "waterfall" on Southern California's "Sledgehammer" trail. No clutch slipping or stalling, he idles the Sammy almost vertical. It then slowly creeps up the face of the rock, eases right on the perfect line in the V-groove, balances through the groove in slow motion and is through the obstacle. No burnt clutch, no stalled motor, in perfect control all the way.

Time to stop or turn before that rock bites your quarter panel. By going slower, you control what you hit and how hard you hit it. Reduces shock loads on axles, drive train and suspension. Torque can be applied more smoothly, thereby less clutch stress. Simple physics that pay off in reduced repair, expenses and less down time.