Rocky Road Outfitters' Transfer Case Mount Bushing Upgrade Kit
Samurai owners know how tough our little Suzukis are, but as with any vehicle that gets pushed far beyond its original design's intent, weak links surface. As we fit larger tires, install traction adding devices, increase the gear ratios and squeeze more power out of the engine, our trucks become capable of playing on increasingly tougher trails. However, these modifications multiply the torque going through the drive train and quickly find the weak links in the system.
Trail carnage is well known to any off-roader. Experienced 4-wheelers know which spare parts to carry with them if they have yet to upgrade the damage-prone components. Tougher clutches, beefier axles, and stronger drive shafts are some of the most common (and expensive) upgrades that must be made to minimize component failure on the trail, but the failure of even a minor component can end a day of fun.
On Samurais, one of the first parts to fail is usually a transfer case mount bushing. These little 1-cubic-inch rubber bushings are designed to isolate the transfer case from the frame, minimizing the transfer of noise and vibration from the drive train to the occupants. On a new, stock Suzuki, they work as intended. Unfortunately, rubber degrades over time, especially when exposed to road grime, salt spray, water and oil leaks that are an unavoidable part of the automotive environment. Combine the degraded rubber with torque multiplication through the drive train from other modifications and the rubber doesn't stand a chance. Torn bushings are well known to Suzuki 4-wheelers.
The Rubicon Trail may be the most famous 4x4 trail in the world. Although it is not be the toughest trail in the world, it has certainly caused its share of carnage, including many torn Samurai transfer case mount bushings. Experienced drivers know to carry a handful of spare bushings because at least one vehicle is sure to wind up with its transfer case flopping around between the frame rails after playing on the rocks. It was after tearing three of these bushings in one day at this year's annual Suzuki's on the Rocks Rubicon trip that Glenn Wakefield of Rocky Road Outfitters decided to solve this problem once and for all.
In the past, individuals have attempted to build their own upgraded transfer case mount bushings to varying success. Some wound up being too weak, self-destructing after only one trail run. Others wound up being too strong, resulting in damage to the frame, the transfer case mount, or the transfer case itself while doing nothing to eliminate the noise and vibration transfer. Since I have torn at least half a dozen bushings before, I also took a stab at designing a better bushing utilizing a bolt and a few shock absorber bushings. It worked well for a short period of time until the bushings tore and the bolt damaged the frame. To prevent further damage, I reverted to the stock bushings and was soon back to my usual schedule of replacing them.
Rocky Road Outfitters calls their new transfer case mount bushing upgrade kit "bombproof." Whereas the stock bushings are nothing but rubber bonded to and sandwiched between two metal plates (each with a threaded bolt end to mount the transfer case to the frame), Rocky Road's design utilizes a solid bolt with four polyurethane bushings. While the bolt provides the strength needed to mount a low-geared transfer case, the poly bushings dampen the vibrations and withstand the elements much better than rubber can.
Replacing the stock transfer case mount bushings with a set of Rocky Road's bushings is simple enough that it does not even require removing the transfer case from the vehicle. Only simple hand tools are required.
The first step is to make sure that it is safe to lie down underneath your vehicle. Firmly set the parking brake. Engage neutral in both the transfer case and the transmission to eliminate any binding in the drive train that could put any stresses through the transfer case and its mounts.
Next, remove the existing bushings from the transfer case mounts. The short mount on the driver's side of the vehicle has one bushing, while the long mount on the passenger's side has two. Do not remove the mounting arms from the transfer case; just work on one bushing at a time, removing the 14mm nut on each end of the bushing to free the mount from the frame and allow the bushing to be removed.
Finally, place two of the new polyurethane bushings between the transfer case mount and the frame such that the small nipple ends of the bushings face each other in the middle. The bolt should be dropped through the transfer case mount, the two middle bushings, and the frame with a washer between the head of the bolt and the top bushing, with the nipple end of the bushing facing up against the washer and the bolt's head. The bottom bushing should be installed with the nipple end facing down, followed by a washer, and finished with the nut. Tighten the nut on the bolt enough to get a little compression out of the bushings, and then proceed to replace the other two stock bushings following the same procedure.
There is no question that these new transfer case mount bushings are much stronger than the stock rubber bushings. The selection of the proper polyurethane bushings was the key to designing these new mounts. While ensuring that the transfer case cannot be torn from the frame, the harsh vibrations that come from steep drive shaft angles and high torque applications are sufficiently quelled to protect the frame and transfer case from damage.
Driving on the road, I immediately noticed less movement of the transfer case's shift lever. My stock drive shafts are forced to soak up just about the limits of their universal joints' capacity, so my transfer case is subjected to lots of vibrations. The old rubber mounts allowed the shift lever to buzz about like crazy; the new mounts secure the transfer case to the frame much more positively, while still providing enough dampening to prevent secondary vibrations. Overall, the interior is quieter and vibration has been reduced.
Off-road is where these new bushings really shine. I no longer have to worry about carrying several stock replacement bushings every time I tackle a hard trail, nor must I carefully monitor the amount of movement in the transfer case's shift lever to ensure that I catch a torn bushing before the vehicle sustains any more damage from a loose transfer case.
Overall, Rocky Road's new transfer case mount bushing upgrade kit is a boon to hardcore Samurai off-roaders. The design has so far proven to be much more durable than the stock bushings, and has netted my vehicle a decrease in vibration and noise. I have personally had a significant increase in peace-of-mind since I know that I no longer must dread the day that I again must lie on my back in the dirt, mud, and rocks fighting to replace another torn stock bushing as soon as I started to have some real fun on the trail.
Upgrading the weakest link in any chain makes the next-weakest link the next in line to fail, and this upgrade is no exception. Even with stock transfer case mount bushings, the mounting arms that secure the transfer case to the frame can be twisted or torn from the same forces that tear the bushings. This happened to me on more than one occasion, so I had already replaced my transfer case mounts with upgraded ones over a year ago. When ordering a set of upgraded transfer case mount bushings, I highly recommend also replacing the stock transfer case mounting arms. Rocky Road also sells these, as do several other companies. Based on my experience, the stock mounts will undoubtedly be a problem if they are not also addressed. Beyond that, I have not had yet found the next-weakest link in the chain. If I find it, I will be sure to update this review.
Rocky Road Outfitters has successfully solved a problem common among hardcore Samurais. With these new bushings, there should be many fewer Samurais seen pulled off to the side of the trail getting their torn transfer case mounts replaced. And at only $21 for the set, upgrading all three mounts costs less than replacing a single torn mount with a new stock bushing!