The site navigation utilizes arrow, enter, escape, and space bar key commands. Left and right arrows move across top level links and expand / close menus in sub levels. Up and Down arrows will open main level menus and toggle through sub tier links. Enter and space open menus and escape closes them as well. Tab will move on to the next part of the site rather than go through menu items.
Enter your truck info so we can recommend the right products for you.
Can't find it? Call us at 866-737-4966 for free advice.
Injectors & Related Items
Water Meth Inj Kits
Thoroughbred Diesel has been your online performance headquarters since 2002. We know how to get the most performance out of your pickup truck and offer all of today's most popular diesel performance products.
Gaskets & Seals
Starters & Alternators
Thoroughbred Diesel offers OEM and diesel stock parts for your diesel pickup truck. At Thoroughbred Diesel, you can
buy stock diesel replacement parts such as injectors, fuel pumps, ball joints,
track bars, turbos, and more for your diesel truck.
Diesel Tips Shirts
Show your support with a Thoroughbred Diesel t-shirt, sweatshirt, or sticker decal.
Floor Mats and Liners
Locking Fuel Doors
Spare Tire Carriers
Make heads turn with custom truck accessories from Thoroughbred Diesel.
In the past, heavy duty clutches were associated with a clutch pedal which was harder to push. We have combined leverage ratio technology with premium friction material to achieve a higher capacity for torque in our clutches, without increasing the pedal effort. Replacing worn forks, pivot balls, bearings and hydraulics will also help. Many people are unaware that, as a clutch wears out, it gets harder to push. Used to the way the pedal feels, most people are surprised by how easy the new system works.
back to top
Any time you increase the torque capacity of a clutch by using high torque friction material, you can expect this. A factory clutch, which engages smoothly, will slip when additional power is introduced. We have spent considerable time, effort and money in an attempt to provide the best possible material, in order to minimize this effect. Sadly, this is one of the many aftereffects that come from turning up your power. One thing you can do to help is to (ever so slightly) increase the RPM of the engine while engaging the clutch.
First of all, the term “clutch chatter" is often misused. Generally, what people are describing is drive train shutter. This phenomenon is most common in trucks equipped with the G56 transmission. Usually, there are many related issues that can cause this problem. For one thing; if you have turned up the power of the engine, and now have a clutch, which transfers that extra power more abruptly, the drive train (which is not built for that) will respond by shaking. Worn mounts, u-joints, rear ends and springs can exaggerate this effect. Instability in the rear end, coupled with resistance from a load, are the main reasons this happens. One of the other things that made matters worse is the fact that (for fuel economy) Chrysler began using 3.43 and 3.55 gears in the rear end. They’re great when you’re cruising down the road in overdrive, but backing up from a dead stop...not so much. There are a few simple and effective things you can do to address this problem.
The noise is a result of the vibration your engine creates, being transferred into your transmission. When you depress the clutch pedal, it disconnects the engine from the transmission. Due to the fact that the original clutch assembly used a sprung (dual mass) flywheel to dampen that vibration, there was no noise. The extra power that it takes to slip a factory clutch is also what over- torques the flywheel, resulting in a system failure. In order for our clutch to handle increased horsepower and torque, a solid flywheel must be used. Considerable effort has been made (by us) to dampen as much of the vibration as possible, while still maintaining the integrity and longevity of the clutch. Again, I remind you that there are some concessions to be made when you turn up your power.
The exact same clutch, put into two different trucks, can produce completely different results. There are two primary reasons why the level of noise can vary.
Although the gear rollover noise does not sound good, no one has ever proven that it causes excessive wear, or ruined their transmission. Keep in mind that most of the trucks with this symptom have exceeded the torque and/or the towing capacity that the transmission was designed for...which is most often the main cause of accelerated wear and/or failure.
When the wheel speed of your vehicle does not coincide with the proper gear in your transmission, the RPM of the engine drops too low and causes a violent shaking of the engine and drive train. Imagine what would happen to an automatic transmission if it wouldn't shift out of fifth gear, and you drove around town that way...it wouldn't last long. Downshifting into the proper gear and keeping the RPM of the engine up is the most important thing you can do to assure you get the most out of your engine, clutch and drive train. If you own a truck with a factory equipped G56 transmission, you may have noticed that the dual mass flywheel dampened most of that vibration (if driven that way), but I can assure you, that is what ruined your flywheel. I know shifting can be a hassle...but you chose a manual.
Too much torque at too low an RPM. I go back to the automatic. If you were driving down the road in automatic overdrive, with the cruise control on, and approached a hill, the system (in order to keep a constant speed) would need to accelerate. The transmission would automatically downshift in order to do so. By keeping the RPM up while accelerating, it is preserving its life. There is a misconception about fuel consumption. People believe that the lower the RPM, the better the mileage, when actually, the opposite is true. All that black smoke you get when you step on it in overdrive is unburned (and therefore wasted) fuel. Keep the RPM up by downshifting into the right gear, and your truck will run much better.
This is a very good question, because most people do just that. The trouble is, it is too hard, with all the variations in terrain, to keep a constant speed. Therefore, you end up accelerating too much in that high gear. Many trucks, with automatic transmissions, set up for towing, will include a button for "tow mode" which locks the transmission out of overdrive. The main reason for that is, the transmission would be constantly downshifting. The best answer is to say; watch your RPM, if it starts to drop too low, rather than stepping down on it in 6th, drop to 5th ...and maybe stay there.
When Chrysler redesigned the clutch system in 2005, they used a self-adjusting pressure plate designed by LUK. This unit, in order to work and adjust properly, used a hydraulic assembly with a limited (shorter) amount of stroke or throw-out bearing travel. When we started using the solid flywheel and earlier style clutch, hydraulics with a longer stroke were needed.
There are many reasons why it's hard to get your transmission into gear at a stop. Faulty hydraulics, installation errors, worn transmission parts and even bad parts from us, could be the problem. Once the truck is back together, it is very difficult to figure out where the problem lies. We go to great lengths to make sure each and every clutch is tested before we sell them to try and eliminate the chance you get a "bad one". Though we are not infallible, it is very rare that we just built the parts wrong. Though the installation of a clutch may seem rudimentary, we see countless examples of mistakes made by unqualified "mechanics", the most common being a lack of understanding of the principles of a clutch system. Many people do not realize how (things like) motor mounts, transmission mounts, crankshaft end-play, drive train slop or worn hydraulics, etc., can affect the way a clutch works. Someone who says "yeah, my tranny's fine", may not have the knowledge to properly inspect one. If a person doesn't realize that: as a clutch wears out, so do MANY critically related parts, they should not be working on that truck. I can say this in all honesty; the places that buy clutches from us and are experts at installing them...never seem to get a "bad one". This doesn't mean they don't run into problems, it just means they understand the process enough to consider all possible factors before blaming the new parts. Let's assume for a moment, that a clutch was installed properly, yet there's still a shifting issue. We have seen cases where everything checks out, yet it is still difficult to drop into 1st or reverse. The only explanation is that, sometimes, the factory transmission and the aftermarket clutch just don't seem to work well together. It may have to do with some level of worn parts inside the transmission, coupled with the fact that there is a clutch that weighs three times more than the original one hanging on it. The inertia created by that spinning mass can make it hard for the input shaft to slow down enough to stab those low gears. Rarely do we just say to a customer, "well, that's how it is". If it comes to that, all we ask is that they understand...things aren't always going to be perfect.
Many people do not realize that a hydraulic system wears out. It does not need to be leaking fluid to signify that it is bad. The internal seals, which are necessary to build the proper pressure, can be worn, allowing the system to lack the original amount of stroke. The first indication that there may be a problem would be the inability to get the transmission into gear. Too often we hear the customer say that it worked fine with the old clutch. This is another example of someone who doesn't really understand how the whole thing works. When a clutch wears out, the levers of the pressure plate work their way toward the transmission, causing the slave cylinder rod to compress into the body of the cylinder. When the new clutch is installed, and the levers are back down (closer to the flywheel), the slave rod is then re-extended and will often lack the original amount of total travel needed to disengage the clutch. If you start your truck with the transmission in gear, and it doesn't want to creep (or lunge) forward, slowly let out on the pedal. If the clutch engages when the pedal is a couple inches off the floor, your hydraulics are functioning properly. If it grabs right at the floor, consider replacing it.
What you are talking about is the age old practice of downshifting. Even though we all learned that this is an acceptable way to slow down...it's really not. If a person is in the habit of driving this way, they will wear out the drive surfaces of their clutch well before they should. A little known fact is that a clutch is designed to torque in one direction only. When you downshift, you send a reverse thrust through the drive train, which causes the dampening portion of the clutch disc to torque in the wrong direction. This will accelerate the wear of the clutch.
The simple answer to that question is...no. The SDD was not designed for that purpose. That being said; I know people do it anyway. Some get away with it, and drive home (with both their feet), and some do not. The risk is that the amount of heat produced when you launch with a sled behind you, can fracture (and fragment) the cast iron plates in the clutch. Competition clutches are made out of steel for that very reason. Safety is a factor that should be considered above all.