Tom Wood's Drive Shafts, 1350 Front; Wrangler JL & Gladiator JT w/ Factory Axles

In the past few years, this has been become quite a hot topic for debate. I'll get to the bottom line first, then explain the basis for my opinion.

Bottom line on strength: The non-greaseable joint is slightly stronger than a greaseable joint. The exact number, how much stronger, is unknown and we do not believe it to be very significant.

Bottom line on wear life: A regularly greased greaseable joint will outlive a non-greaseable joint. But a non-greaseable joint will outlive a greaseable joint that does not get greased properly.

Now I will elaborate. We have asked two of the major universal joint manufacturers who make non-greaseable joints for the numbers. Sure they are stronger, but how much stronger? We have asked them to give us the data, to tell us that a non-greaseable joint breaks at X foot pounds or that a non-greaseable joint is X% stronger than a conventional joint. So far, no one has been able to provide those numbers. I believe that it is kept a mystery because the truth is not as impressive as they want it to be. There is certainly something to the idea that having a solid joint makes for a stronger joint. Especially when talking about eliminating a hole for a grease zirk from the body of the joint. Side note, this is why we designed our Gold Seal 1310 series joints to have the grease fitting in the end of the cap instead of the body of the cross like a traditional joint shown below.

But there are also the holes that go through the joint from end to end, the ones that form the channels through which the grease flows. We don't believe these holes to have a great effect on the strength of the universal joint. The main reason for this is the location. They are in the center of the trunnions where the load is not concentrated. Universal joints are case hardened, the material at the center which gets removed when drilling for grease channels is soft and was never a source of much strength to begin with.

As far as wear life goes, and in our opinion the most important factor to consider when deciding which joint is right for you, the biggest question to ask yourself is "Am I actually going to grease my drive shaft?" If you are, get a greaseable joint. If you aren't, get a non-greaseable joint. Non greaseable joints are sealed better than greaseable joints. They are designed keep the grease in and the dirt and water out. However, there are two ways of thinking about it. One, you have a joint that you don't have to grease. Two, you have a joint that you can't grease. Even the best sealed joint will eventually dry up, the seals will crack, and moisture will find its way in. When that happens, the only thing you can do is to replace the joint. A greaseable joint on the other hand is something that you have to grease but you also get to grease. As long as you follow a regular maintenance schedule you will never have to worry about a rusty and dry joint. One last thing, and this is a big one, is that just because you don't have to grease your universal joints does not mean you don't have to grease your drive shaft. This is because there are other components that will almost always require a grease fitting. Two notable examples are the center ball in double cardan shafts and the slip yoke.

So there you have it. There is a big list of things to consider when choosing greaseable vs non-greaseable joints. At the end of the day, the right choice is the one you prefer. There is no right or wrong answer and it mostly comes down to personal preference.

Q: Why do we ask for length measurements, haven't we done enough to know what the length is?

A: We have done enough to know that it isn't always what it is supposed to be.

Let Tom Wood Explain.

Over the years, we have built well over 10,000 drive shafts for the Jeep Wrangler JK alone. We have built countless more for just about any other type of Jeep, Toyota, Ford, Chevy, Land Rover; all of it. We know that there are often consistently standard lengths for some vehicles, but we also know that some vehicles have wild variations in drive shaft lengths. Rather than get into all the details of all the different vehicles, I will address the low hanging fruit, the Jeep Wrangler JK.

Different Lifts.

Take a look at all the different lift kits available for a Jeep JK. The amount of options is dizzying. 3” is 3” though, right? It shouldn’t matter whose 3” lift you install, the length will end up being the same, right? Wrong. I believe the biggest factor here is control arms. Control arms are basically the pivot arms that horizontally attach your axle to the frame. Some lifts come with new control arms, some do not. Some come with fixed control arms, some come with adjustable length control arms. So, if one 3” lift uses the stock control arms but another comes with control arms that are 1” longer than stock, that second kit is going to require a longer drive shaft. It gets even more complicated when they come with adjustable control arms, these are variable length and it is up to the installer to decide how long or short to adjust them. Because there are so many different lifts and different lift manufacturers, it is impossible for us to keep track of all these variables.

Anomalies.

Here is an example of something we have encountered before. One of our vendors, they do a lot of installations of lift kits. They were doing a lot of the exact same lift on the exact same type of Jeep. Whenever they would order, they would just order the same length shafts they ordered the time before. This was fine, it got them the correct fit shafts for half a dozen vehicles. Until one day the front shaft didn’t fit, it was 2 inches different than all the other times. On paper it was the exact same build but for whatever reason it wasn’t the same length. No one could figure out why, but why didn’t matter, what mattered is that it didn’t fit. Stories like this are not common, but they do happen. We have all been there, we go to the local parts store and the part we get doesn’t fit our vehicle correctly. It is supposed to fit, but it doesn’t.

Complexity of Different Builds.

Sometimes it is straight forward, 3”-4” lift on a JK. But sometimes people will do motor swaps, axle swaps, or other things that affect the length of the shafts. This can get real complicated and difficult to keep straight.

What Does It Mean for a Drive Shaft to Fit?

Just because you can get a drive shaft installed, does not mean it fits. Drive shafts do compress and extend, but a common misconception is that they compress and extend to allow them to be a bit of a one size fits all. This is not the case. The reason they do is basically the same reason your shocks compress and extend. Because as you go down the road and your axle moves up and down they need to get longer and shorter. There is some leeway for fitment but not a lot. For most shafts, anything more than 1” off from fitting correctly could spell disaster.

One Reason We Request Measurements When Others Don’t, is Because We Care.

We want to make sure that whatever you buy from us is going to be the right thing and is going to work well for you. We could send out more “universal fit” shafts and just figure that it is your problem if it doesn’t fit. But that’s not who we are.

Measuring is Easy.

It doesn’t matter if the drive shaft is installed or removed. You simply measure the distance from your transfer case yoke (or flange) to your axle yoke (or flange). It doesn’t have to be perfectly accurate; the nearest quarter inch is fine. It takes less than a minute and can be done in your driveway.

It doesn’t affect the price or the delivery time. We don’t charge more or take longer to build custom shafts. You might as well get a perfect tailored fit.

All that being said. . if you can’t measure, or just plain don’t want to there are standard lengths that we can go off. If you are getting shafts for a JK we won’t require measurements, just recommend it. For other vehicles however there are enough different length possibilities that we will require a length measurement. It is quick, it is easy, and it could save you from getting the wrong drive shaft.

Wrangler JL & Gladiator JT front drive shaft lengths can vary a bit and once the drive shaft is manufactured the order cannot be changed, canceled, or returned. Because of this, we require a length measurement before processing the order and having the shaft built. Measuring is simple and easy, you can see here below the process for measuring for your needed drive shafts and measurements can be made with or without the stock drive shaft installed. A measurement from lip of flange on the transfer case to the face of the flange at the differential with the Jeep on the ground is required as shown below.

Measurement is best taken with the vehicle parked on flat ground at normal ride height. Measure from approximately center height (the 3 or 9 o’clock position) for the best measurement. If you have a lift installed on the vehicle, you may need something to rotate the differential for the CV type drive shaft to function properly. This is typically done with adjustable control arms and we recommend adjusting the control arms on the suspension before measurement. Pinion should be 1 to 3 degrees lower than the slope of the drive shaft and alignment should be as shown below.

Tom’s Story.

Tom Wood’s is not just the name of a company, Tom Wood is a person. In 1979 Tom started working for a local drive line shop because he “needed a job” and a local drive line shop was hiring. He worked for that company for 20 years. Sometime in the mid ‘90s, with the emergence of off-roading as a sport, he saw an opportunity to do something new and do things differently. He quickly built a name and reputation for himself as the guy to go to for specialty off-road drive shafts. However, management of the company he worked for didn’t share his vision. He decided to start his own company, to see what could be achieved by focusing solely on off-road drive shafts. In 1999 he quit his job and with virtually no money to get started he founded Tom Wood’s Custom Drive Shafts. He started small, working by himself in a small rented garage in a bad part of town, sometimes staying and working 2 days straight with no sleep. Diligence and hard work eventually allowed him to hire an employee, then another, then more. Eventually He was able to buy a bigger building in a better part of town and hire even more people. He now owns 7,200 square feet of production and warehouse space and employs 14 full time people. Today, the name Tom Wood is synonymous with off-road drive shafts. Tom still comes to work every day and he is still part of the company. These days he mostly does things like working with our suppliers and answering emails, but he still answers the occasional phone call. Over the past few years Tom’s son, Shawn Wood, is stepping in to take over management of the company so that Tom can spend more time doing the things he enjoys.

Our Story.

Our crew is very experienced. Half of our employees have been part of the company for 10 years or more. Most of our phone staff are former co-workers of Tom and have been working in the industry for over 20 years. If you have ever called us with a question or to place an order, you will know that our staff is incredibly helpful and knowledgeable. Any time you have questions about anything drive shaft related, give us a call. It is our office staff’s full-time job to assist you and answer your questions. Even if you don’t plan on buying anything from us, we’re happy to help. We believe that knowledge should be free, think of it as a public service. It is not our job to “sell” you anything, we genuinely just want to help you to find the shaft or solution that is best for you and your individual needs.

Tom Wood’s Custom Drive Shafts has always been a family company. Tom’s son Shawn started working for the company shortly after we opened, when Shawn was still in high school. Tom’s nephew Jason is our shop supervisor and primary builder. In addition to the Wood family we have the Reardon family. Troy and Karry Reardon have both been key employees for the better part of 20 years. Each of them has or have had sons and other relatives employed here at one time or another. Many of our other employees are people who simply replied to a job listing, but everyone who works here is more that just an “employee”, they are all part of the Tom Wood’s family.

Focus on Quality.

Quality has always been Tom Wood’s number one focus. We have never wanted to be the cheapest or even the biggest, only the best. We believe in the business model of creating the best product available and offering it at fair prices. Our brand reputation has been built the hard way, by always holding ourselves and our products to the highest standards. This will never change.

Processes.

Every drive shaft we sell directly to the customer is built specifically for that customer. Whether it is something that is completely unique or something that is fairly standard we build the shaft the way you the customer orders it. None of our drive shafts are pre-made. This means that the shaft you get from us is tailor made with your needs and your dimensions in mind.

Here’s how the process works. A customer places an order, either through our website or over the phone. If it’s ordered over the phone, we ask you all the important question to ensure that you get exactly what you want and need. That evening our production crew cuts the tube for your shaft and makes sure that all the necessary components are assembled.

The following morning the crew comes in at 5:00am and starts the build process. First the shafts are pressed and welded. One end at a time we press the parts into of the shaft into the tube, straighten it, weld it, then re-straighten it. We ensure that the shaft is straight within a few thousandths of an inch. Once both ends are welded, and the shaft is straight it moves along to the balancing department. To avoid warping or damaging sensitive balancing fixtures and equipment we don’t build and balance shafts on the same machines. Drive shafts are put into state of the art Axiline balance machines and balanced at 3,300 drive shaft RPM. Once the shafts are balanced, they move on to the paint and package department.

The shafts are then cleaned with a degreaser and put into our paint booth. Using an automotive type air-sprayer, we apply a fast-drying black paint. When the paint is dry, we grease all the grease fittings and put them on a rack to be packaged. They are then packaged in special made double wall boxes and shipped via UPS. At about 4:30 Utah-time they are loaded onto a UPS truck and sent on their way to our customers, all over the United States and beyond. This entire production process usually takes place within about 24 hours. Almost without exception, all the shafts we build are shipped one business day after being ordered. Getting things shipped quickly is very important to us and something we take great pride in. We never allow ourselves to get behind schedule. You get a custom tailor-made drive shaft without any extra wait time and without having to pay an extra price.

Materials.

Nearly all the components we use are Neapco, Spicer, or Tom Wood’s brand. Everything we use is sourced for its superior quality and/or function. In addition to using Neapco or Spicer, something that makes us unique, is that we have our own parts made. There are some things that other manufacturers either don’t make at all or don’t make the way we think they should be made. Because of this we have invested into having many parts manufactured for us exclusively and exactly to our specifications. This could be anything from a minor design or material change on an existing product, to a flange or yoke that didn’t exist, or even something as complex as a completely original slip yoke eliminator kit. Here are some notable examples of Tom Wood’s unique parts. Super Flex offset universal joints, an innovative design which allows for greater flexibility. Our Gold Seal joints; designed for strength, serviceability, and with the best warranty in the industry. Forged and/or steel yokes, for superior strength over traditional cast iron yokes. Flanges to fit vehicles that nobody else seems to care about such as Toyotas and Suzukis. Slip Yoke Eliminator kits for NP242 and NP241C transfer cases.

All the tubing we use is USA made DOM (drawn over mandrel). We use tubing with wall thicknesses ranging from .083” to .188”. The heavier tubes being used when the customer’s planned use make dents and other rock damage a concern.

We have a huge inventory. This is important for two reasons. One is that we are almost never out of stock of anything, we are always ready to build whatever it is you need built. The other reason is that by buying in super-bulk quantities we can control costs and build premium quality products at competitive prices.

Ethics.

There is more to life than just making money. At Tom Wood's we believe in conducting ourselves with integrity and doing the right thing. That means treating people the way they deserve to be treated, our staff and our customers alike. It means taking accountability for things, And it means supporting responsible recreation by partnering with groups such as Tread Lightly.

Diagnosing and identifying the cause of drive shaft vibrations and noises can be quite frustrating. This will help you to follow the clues and hopefully find the source of those aggravating and worrisome drive shaft noises, vibrations, and shudders.

There are different types of drive shaft vibrations. There are angle related vibrations and there are dynamic vibrations. Angle related vibrations are caused by a u-joint running through improper angles. Dynamic vibrations are things like a bad balance, vibrations that are a product of weight and speed. I’ll go over the symptoms of each below.

• Angle related. These are typically felt at lower speeds, from 0 to about 40 mph. These are also worse on heavy throttle and load, when accelerating or going uphill. Angle related vibrations are often described as a shudder and usually get better or go away when you let off the gas or shift into neutral. Another sure way to know it is angle related is if the vibration started immediately after installing a lift.
• Dynamic vibrations. These are worse at high speeds, usually 50 mph and up. The faster you go the worst they get. Letting off the gas either makes no difference or it makes it worse. If letting off the gas makes it worse it usually means that there is a loose part which is rattling around when unloaded. Another good indicator of loose parts is a vibration that gets worse and worse over time. This means that whatever is worn and loose is wearing more and becoming more loose whereas an angle issue does not change over time. Lastly, if your drive shaft is several years old or older it is almost certainly a bit worn which could be causing the vibrations.

If your symptoms seem angle related you may want to measure your angles and adjust if necessary.

If it seems more like a dynamic vibration it could be any of the following:

• A poorly balanced shaft. Most reputable drive shaft shops will get this right but It is possible, even we sometimes get it wrong.
• A loose part. This could be on the front or rear, both should be checked. on some vehicles, even in 2WD the front shaft is spinning passively. A good test for loose parts is to set your park brake and/or chock the wheels, put the vehicle in neutral (not running though), then scoot underneath your vehicle. Give each drive shaft a good hard shake up and down. If you can feel anything moving and/or hear a knocking sound then there is something loose that needs to be replaced or tightened.
• A bad transfer case yoke or pinion yoke. This is not common but it does happen. The yoke on the transfer case could be machined a little off center which would cause the entire drive shaft to run off center. This in turn causes the entire drive shaft to run off center and vibrate.
• Something else entirely. There are a lot of moving parts on a Jeep or truck and a lot of things that could be making noises and vibrating. Many times it is not a single source but a vibration will actually be a combined result of several factors.

Drive shaft RPMs are often an important thing to know and consider when diagnosing drive shaft vibrations. For example, if a shaft is only spinning a few hundred RPMs it is very unlikely that the vibration is a dynamic vibration. Also, sometimes people will gear their ring and pinion very low (higher number means "lower" gearing) which will cause their shaft to spin abnormally fast at normal driving speeds. The target for highway driving for most vehicles is to have the drive shaft spinning at around 2,500 to 2,800 RPM at 60 mph. If it is over 3,000 RPM you might have a situation in which your drive shaft basically thinks it is going 100 mph while the rest of the vehicle is only going 80.

Size and strength. The 1310 series joint is what you would expect to find stock in most Jeep or small trucks. A 1350 series joint/shaft is what you might find in many full size trucks. While it's not 100% accurate, you could say that a 1310 is a "half ton" joint and a 1350 is a "one ton joint".

Any Tom Wood's drive shaft is fully greased before we ship it out. So initially, all you need to do is install it. Down the road however you will need to grease your drive shaft to ensure a long life. A good guideline to start with is to grease your shaft every oil change. If you go wheeling and drive through a lot of dirt or water, grease your shaft as soon as you get home. This will flush out the contaminants before they have a chance to do much harm. We recommend a good quality grade 2 grease with calcium sulfonate as an additive, but any grease will do. Just don't overlook that CV center ball!

More specifically people will ask "How much of the blue should be showing?". The blue doesn't matter, it doesn't always start in the same spot so you should really be looking at how much spline is showing. The answer though depends on the type of spline you have. For Tom Wood's drive shafts there are mainly two types of spline; the S spline and the X spline. If you have the S spline, there should be about 1.5" of the smooth bar showing. For the X spline you'd measure from the dust cap to the center of the weld, this should be around 3 1/4". As long as you are within a half an inch or so of these numbers, consider your shaft a good fit. If the amount of spline you have visible is much more or less than what is recommended, you may need to have your shaft lengthened or shortened.

Below you can see what a shaft built with our X spline should look like when installed in the vehicle. The second photo is a side by side to give you an idea of how much spline would still be inside the slip yoke under normal operating conditions.

In the above photo, you can see the difference between the total length of the spline and the usable length. For safe and stable operation, the slip yoke and spline should maintain at least 2 inches of engagement at all times. That means that however long your spline is, you can subtract two inches from that to get your usable range of travel. You can see in the above photo that usable range is in red. The section shown in blue needs to remain inside the slip yoke at all times, even under full axle droop.

There are a number of reasons you might be having repeated problems with drive shafts or u-joints. One is that your drive shaft and the shaft's components are just too small for the application. If you've got a Jeep with a HEMI engine, Dana 60s, and 40+ inch tires but you're still running the stock size joints in your drive shaft, it is time to upgrade to something bigger. Another common problem is over-flexing and binding; this could be because you have a lot of lift and the shaft is running at too steep of an angle under full suspension droop. In the end, drive shaft vibrations and noises can be for any number of reasons; whether the stock one is just worn out or your Jeep has modifications that call for an upgrade over stock a Tom Wood's drive shaft very well be the quality solution you need to get back to using your Jeep your way.