By now, most Jeep JK owners have taken a peek under their rigs, only to find drive shafts that are totally unusable if you plan to install a suspension lift. The stock drive shafts are of the CV variety and are not new to the Jeep brand.  | Factory Rear Jeep JK shaft |
The Grand Cherokees have used them with success and add to a smoother running drive train. Jeep decided to incorporate similar shafts into the new JK, with little thought to those who might add two to six inches of lift. The shafts work decently in stock form but once a small amount of lift is added, vibration starts after only a few thousand miles. The CV joints are not designed to run at any angles at all. In fact, we were witness to an exploded CV joint on the trail while only running a 2.5 inch budget boost and 35’s. Of course, the severity of angles is less on the longer wheel based Unlimited Jeep, however, many owners are lifting their four door vehicles four to five inches or more. The JK drive shafts are externally splined, which means if you smack one of the shafts on a rock and dent it, the shaft will not work properly. This is something that even an unmodified Jeep JK owner must think about when off-road. In our experience, most Jeeps that are taken off road need to have the drive shafts upgraded for longevity and strength. Our Unlimited Rubicon was a perfect candidate for some new Tom Wood's Custom Drive Shafts. Not only did it need some strength upgrades, but the joints on the stock shafts were starting to vibrate badly and the front boot had already torn and was splattering the chassis with grease.  | Notice the grease spattering from the worn joint |
With less than 8,000 miles since the four-inch lift was installed, the factory units were shot!  | Severe angles at the front cause quick failure |
We contacted Tom Wood's Custom Drive Shafts and Tom Wood answered the phone. In the past, we have always been impressed with the customer service that was provided by Tom Wood and the rest of his staff. We discussed what we wanted out of the JK and the current problems it was suffering from. Rather than just build shafts for a general Jeep JK application, Tom recommends that each Jeep owner take proper measurements for custom length drive shafts. He also provides a handy picture on his website that illustrates the exact points of measurement to take. http://www.4xshaft.com/JK-jeep.html It was decided that 1310 fronts and 1350 rears were just right for what we needed. Normally, the 1310s would be plenty strong and are extremely tough joints, however, we felt that 1350s in the rear will provide a little more confidence when on the throttle with 37 inch tires. There is not nearly the stress on the front of the drive train when off road so the 1310s were the perfect combination. By going with the 1310 fronts, it also saves a bit on the pocket book.  | Tom Woods flange compared to factory units |
Tom Wood's JK shafts also include his new flanges. Most companies are building replacement shafts that bolt up to the factory JK drive flanges via an adapter. The adapter works fine, unless you break the weld yoke portion. Then the probability of finding a replacement part could be very slim. It also is quite long and places the center of the U Joint further from the bearing, causing more stress on that bearing. Tom’s new design incorporates replacement flanges forged from solid billet steel, allowing the use of any “standard” mating flange. The shorter flange will also require a longer drive shaft, which will decrease the possibility of poor drive line angles, especially on the two door JKs. It took about two minutes to measure and another minute to email Tom Wood the numbers. We received an email back the next morning, letting us know that our drive shafts would be shipped out that afternoon. Wow! Custom drive shafts in two days! Shipping was free and for an extra $15, the shafts were fully polished to a shine and clear coated for long lasting protection.  | What a difference! Tom Woods Shafts are polished to a shine |
Once the drive shafts arrived, another call was made to Tom Wood for a few tips on the install. Tom was gracious enough to take the time and answer all of our questions, also providing us with information on tools needed and torque specs. The only uncommon tools needed were a two or three arm gear puller and a 32mm socket for the rear pinion nut, the same nut used on the Dana 60. It takes a lot of muscle to remove the factory pinion nuts that are set at a torque of 200 lbs. Once removed, the factory flanges are easily removed with your puller.  | The puller simplifies the job |
You can reuse the factory pinion nuts and re-torque them to 150 lbs., not forgetting the red Loc-Tite on any threads. New nuts are supplied for the transfer case output shafts, as well as all Grade 8 hardware to complete each end.  | Tom Wood supplied this new nut for the transfer case output yoke |
The rest of the install is a simple bolt on affair. These more traditional drive shafts also allow the JK owner to achieve more suspension travel without damaging the driveline. During extreme travel, the factory CV joints can not flex to the angles needed and still function properly. The JK exhaust and cross member can also interfere in the front during down travel with the factory shaft. These problems are eliminated with the new Tom Woods Shafts and we have recently upgraded to longer shocks for that additional articulation! The shafts looked so nice that we thought we might be too scared to scratch them on rocks, but tough they are enough to go at any trail on earth.  | Installed and ready to rock |
Install was incredibly simple! We’ve heard many Jeep owners that were intimidated by the sound of having to remove the drive flanges. We feel that anyone that can turn a wrench can easily do this install in less than five hours. Tom Wood's Custom Drive Shafts came through on this project and has this new product available now for all JK owners. We feel that this basic swap is a must for anyone who has already lifted their new Jeep or plans to. For the more mild, weekend wheeler without a lift kit, this drive shaft upgrade should also be a serious consideration to rid their JK of what is, perhaps, the weakest link on the Jeep. So, how did they work on our project JK? Vibration is gone! Drive shaft angles look good. And yes, we’ve already put some scratches in those beautiful shafts! Visit Tom Woods Custom Drive Shafts website to find out more about their bullet proof, new Jeep JK drive shafts. www.4xshaft.com  | Front shaft all buttoned up |
 | Front of the transfer case yoke to the double cardan joint |
 | Rear out put shaft with flange |
 | Final touches on the rear |
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