Featured Products and Specials
Like most things on modern automobiles, the simple piece of gearing known as a differential has seen constant refinement and experimentation - leading to a range of types each with their own advantages and disadvantages. The concept of the differential — that is, to allow wheels mounted on the same axle to rotate independently of each other — is an ancient design, with the first known instance of its use recorded in China during the 1 st millennium BC.
The advent of engines powering wheels to propel a vehicle instead of merely dragging them via horse added a new problem to overcome — how to allow independent rotation while still being able to power both wheels. But this was far from ideal as it meant they were underpowered and encountered frequent problems with traction on anything other than firm, level ground. Eventually this led to the development of the Open Differential before other more complicated types were developed to overcome more complex driving conditions.
A differential in its most basic form comprises two halves of an axle with a gear on each end, connected together by a third gear making up three sides of a square. This is usually supplemented by a fourth gear for added strength, completing the square.
This basic unit is then further augmented by a ring gear being added to the differential case that holds the basic core gears — and this ring gear allows the wheels to be powered by connecting to the drive shaft via a pinion.
In this example you can see the three sides of the internal gearing that make up the core mechanism, with the larger blue gear representing the ring gear that would connect to the drive shaft.
The left image shows the differential with both wheels turning at the same speed, while the right image illustrates how the inner gears engage when one wheel turns slower than the other. This gearing arrangement makes up the open type differential, and is the most common type of automotive differential from which more complicated systems are derived. It does also benefit from its basic design being relatively cheap to produce.
The disadvantage of this type is that because the torque is split evenly between both wheels, the amount of power able to be transmitted through the wheels is limited by the wheel with the lowest amount of grip.
Once the traction limit of both wheels combined is reached, the wheel with the lowest amount of traction will begin to spin — reducing that limit even further as there is even less resistance from the already spinning wheel. The locked or locking differential is a variant found on some vehicles, primarily those that go off road.
It is essentially an open differential with the ability to be locked in place to create a fixed axle instead of an independent one. This can happen manually or electronically depending on technology in the vehicle.
The benefit of a locked differential is it is able to gain a considerably greater amount of traction than an open differential. One disadvantage of locked diffs is called binding, which occurs when excess rotational energy torque is built up within the drive train and needs releasing — typically achieved by the wheels leaving the ground to reset the position.
Or by simply releasing the locks once they are no longer needed. Welded differentials are essentially the same as a locked differential, only it has been permanently welded from an open differential into a fixed axle also known as a spool diff.
There are two categories which use different forms of resistance to achieve the same effect:. This type of LSD surrounds the same core gearing seen in the open diff with a pair of pressure rings, which exert force on two sets of clutch plates positioned alongside the gears.
This provides resistance to the independent rotation of the wheels changing the effect of the differential from open to locked — and providing it with the increased traction this type benefits from over an open differential. In this cutaway, you can see the the pressure rings also cut away surrounding the core gears, which are forced apart by the central gear pins pushing against the angled surfaces under rotation.
This movement pushes the pressure rings onto the clutch packs yellow and blue on either side, generating resistance and changing the behaviour of the axle from an open to a fixed type of effect.
The downside to mechanical LSDs is they require regular maintenance to keep operational and are prone to wearing out completely, making for an expensive part replacement. The second type of limited slip differential, they instead use a thick liquid in place of clutches to create the resistance needed to alter the differentials behaviour between open and locked. VLSDs are also able to direct torque more effectively to the wheel that has more traction.
Because the fluid acts to be resistant under speed, if a wheel ever loses traction and spins the difference in speed between the two wheels inside the differential creates more resistance on the slower moving wheel - channelling more torque from the drive shaft to it. VLSDs do become less effective with prolonged use, as the fluid heats it becomes less viscose and provides less resistance. It also cannot lock as fully as a mechanical LSD due to a fluid being unable to provide absolute resistance within an adequate space.
A disadvantage with both mechanical and viscous LSDs is that the system does not always channel torque effectively during high speed cornering, as it can interpret the faster moving outer wheel as losing traction. The Torsen Tor que — Sen sing differential employs the use of some clever gearing to produce the same effect as a limited Slip Differential without the need for clutches or fluid resistance.
These sets of worm gears acting on each axle provide the resistance required to enable torque transfer, which it then achieves by having the worm gears in constant mesh with each other via connected spur gears.Before you embark on the rebuild and start scouring local scrap yards and online websites, it will be helpful to understand what to look for and what to avoid in these axles.
First, you need to understand some fundamentals of the Ford axles to help guide your quest. I have spent countless hours over the years collecting, reading, and studying old shop manuals, supplier reference documents, SAE papers, and even vehicle manufacturer reports and notes. Some of this information is very important as it is becoming more and more difficult to find documentation on axles and differentials that were built more than 40 years ago. I have also spent many hours in scrap yards and visiting and interviewing the experts in this field along with years of building numerous axles myself.
In this chapter I share a summary of decades of work on these axles. As part of my research, I went to renowned Currie Enterprises and gathered one of just about every different 9-inch axle variant. I put together a whole collection of housings and third members. This is a sampling of some of them.
Here is a quick visual summary: The housings do not have dimples on them and have an oil drain plug. The s and s have two dimples on either side of the housing and some have drain plugs. The s to s still retain the dimples but also have an oil level plug in the back cover. The Ford 8. There is typically a stamped steel cover that must be removed to gain access to the internals. This chart serves as a general guideline for axle fl ange-to-fl ange width based on different models and production years.
I have included the narrow 8-inch axles for reference. The narrowest production 9-inch axle is If measuring the drum-to-drum distance, add. An assortment of Ford 9-inch axle stampings is welded together to create the housing. The cast-iron third member is installed from the front of the housing. The third member supports all of the gears and bearings, which allows for easier gear ratio swaps if you have multiple third members.
I reference these axles based on the ring gear nominal outside diameter in inches. The fundamental difference between these axles is how the gears are supported and which end of the axle housing front or back that they are assembled from. It may seem strange to begin by comparing the 8-inch to the 9-inch axle, but there is an important distinction to make since the 8-inch axle is weaker than the 9-inch. Many people are not aware that Ford made a smaller banjo axle and confuse the 8-inch for a 9-inch.
The 8-inch was introduced in and is found in many lower performance Fairlanes, Mustangs, Falcons, Comets, Cougars, and Pintos, just to name a few of the applications.Drivetrain Automotive Parts Warehouse. We offer many parts to enhance your vehicle's performance, including used and re-manufactured parts to reduce your costs. These include:. To help save fuel, improve performance and extend vehicle life, we offer a number of products for your automobile, recreation vehicles, motor homes and pickup trucks.
We also offer a series of diagnostic tools technical notes that can help you determine the cause of your vehicles mechanical problems. For further fuel savings, click on our link: save gas and diesel fuel, find out where to buy fuel. Drivetrain is a leading supplier of discounted parts and accessories for domestic and foreign cars as well as light, medium, and heavy-duty trucks. If you are having problems with your car or truck, you can rely on us to provide the parts and the information needed to get you back on the road.
We are your one-stop store for automotive parts online and our warehouse is stocked with products to fix, improve, and enhance the quality of your vehicle. At Drivetrain. We stock everything from high-performance driveshaft assemblies and OEM replacement clutches, to overdrive units and active suspension systems for improved efficiency and safety, all geared towards ensuring your vehicle reaches its potential.
Using our exclusive interactive catalogue and secure online checkout, you can purchase the part you need in minutes and have it shipped to your door immediately.
Drivetrain - Ring & Pinions, Transmissions & Transfer Case Parts
Alternatively, you can find the right component with help from our trained technicians, by calling the order desk at Log In Username. Login Forgot Your Password? Forgot Your Username? New Customer? Create an Account. My Account Orders list Wishlist Checkout.
We offer discounted parts and accessories for domestic and foreign cars, plus light, medium and heavy-duty trucks including 2WD, 4WD Off Road Vehicles. We Ship World Wide! Tech Supportor Monday - Friday am to pm West Coast. We offer the parts and information you need to get your vehicle back on the road. Differential Covers. Transmission Pans. Posi-Lok Vac Shift Motor. Auto Transmission parts. Hard Parts Automatic Transmission.
Overhaul Kits Automotive and Trucks. Audi Automatic Transmission Overhaul Kit. Daewoo Automatic Transmission Overhaul Kit.Chevy and bolt axle assemblies have been standard equipment on GM passenger cars, muscle cars, and trucks for decades. The rugged, reliable, and efficient Chevy bolt has established itself as the preeminent rear differential for GM muscle cars since its debut in However, the smaller bolt unfairly gained the reputation as a weak and inadequate rear end for high-performance applications.
But there are several models in the bolt line-up. The smaller 7. However, the 8. The GM bolt rear end is quite possibly the most misunderstood and undervalued rear differential ever created. Even though it has been used in every major GM rear-wheel-drive platform, the bolt has a bad reputation for being a low-performance unit. Nothing could be further from the truth.
The bolt can handle just about anything you throw at it, as long as you use the right axle, either the 8. That is the great caveat; there are four sizes of bolt GM rear ends: 7.
These sizes refer to the diameter of the ring gear, and the one you use makes a big difference in the performance potential. The 8. Also, these surfaces run cooler because of their sheer size.
This is the Moser Engineering bolt axle assembly. As you can see, the Chevy bolt differential is one stout axle, and it was the rear axle of choice for GM muscle cars and many GM competition cars. Big-block Chevelles, Camaros, and other GM high-performance vehicles were fitted with the bolt limited-slip axle to maximize torque transfer and traction. Photo Courtesy Moser Engineering. You need to be able to accurately identify the GM bolt. Therefore, you need be able to choose the more desirable 8.
Identifying the bolt axle is easy. The nomenclature actually refers to the number of ring gear bolts. The outer cover matches; 10 bolts hold the cover onto the housing. This ring-and-pinion gear has suffered catastrophic failure. The key to identifying the 8. Inside the 8. The pinion diameter is 1. The axles are retained by a set of C-clips on the inner end of the axle shaft inside the carrier.
Most 8. These should be square blocks, each with the outer side 90 degrees vertical to the road and the bottom-side surface horizontal to the road. The pinion shaft diameter is 1. Buick and Oldsmobile bolt-in axles mount at the bearing flanges on the housing ends. They retain the axle shafts in the event of a failure.Select from a broad range of available options and upgrades to configure the perfect rearend for your build.
The Currie Extreme 60 front axle for the Jeep Wrangler Jk, is designed for severe off-road use with tires up to inches and V8 horsepower. The high-pinion design features Currie's exclusive rotated center section with ring gear load-bolt, a combination that delivers superior obstacle slide-over and unmatched gear strength.
If you seek out the most challenging routes and toughest obstacles to conquer, the Extreme 60 axle set is a natural choice. The F9 fabricated housing features a heavy-duty CNC formed and gusseted center section that reduces unsprung weight by more than 50 pounds compared to a cast center. The F9 is designed for severe off-road use with up to inch tires and V8 conversion horsepower. The F9 9-inch fabricated housing features a heavy-duty CNC formed and gusseted center section that reduces unsprung weight by more than 50 pounds compared to a cast center.
The trail Following the introduction of our 9-inch axle assemblies for Jeep Wrangler and Gladiator vehicles, we have received many inquiries regarding the diffe Register Log in Shopping cart 0 You have no items in your shopping cart. Personal menu. GM Vehicles. Ford Vehicles. Mopar Vehicles.
Jeep Vehicles. Toyota Vehicles. Currie Third Members. Currie Axles. Builder Components. Parts Department. Promotional Items. Featured Products. Complete, ready-to-run, drop-in nodular iron case 9-inch third member set up for spline axles.
Complete, ready-to-run 9-inch nodular iron third member set up for spline axles. All rights reserved.National Differential now features NO upfront core charge! We have a lot of our customers asking about our remanufactured differentials and transfer cases. They always want to know what remanufactured means and whether it is going to provide them with the quality parts that they need for their vehicle.
We take pride in all the parts that we offer. Maybe it's because we are inspired by the beautiful Colorado Springs area where we are located. With the smell of the fresh mountain air and the incredible views of Pikes Peak, we are inspired on a daily basis. It's what allows us to go above and beyond for our customers — and we have been doing so for over 34 years. When we use the term "remanufactured," it means that we disassemble the differential, restore it to the original factory quality, then proceed to reassemble the part.
This allows you to shop with confidence knowing that the remanufactured differential that you buy from us will help you to get your vehicle back on the road as though your vehicle was brand new.
There are quite a few reasons why we offer remanufactured parts. Understanding why you should purchase these can make it easier to get what you need for your vehicle's repair. One benefit of using remanufactured parts is that if you are looking for a part for an older vehicle, you may not be able to find it as easily. Many manufacturers stop making parts for a vehicle once it is 10 years old.
Parts and Accesory Guide
The second is that remanufactured parts are often going to be considerably more affordable than brand new parts. If you want to get your vehicle back on the road but you have a tight budget for the repairs, shopping for remanufactured differentials may be the best option for you.
The good news is that we have it all at National Differential. If you have questions about our remanufactured products, call us today. National Differential has been remanufacturing differentials for decades. Along with transfer cases, remanufactured differentials are our bread and butter.
Our customers come to us for a variety of reasons; some need to repair a damaged differential, some want to upgrade to a better one, and others are building their own custom rig and need a differential capable of the most extreme pressure.
No matter what brings them to us, they all come for the same reasons: the guarantee of top quality work and affordable prices. We offer a wide inventory of remanufactured differentials for vehicles of all makes and models. We make it easier for you to shop for the parts that you need without having to go up and down the various aisles of a parts store or hanging out at your local chop shop hoping that the vehicle you need will come in.Our Case IH online parts catalogs are the most advanced on the internet, showing live inventory, pricing and availability.
Knowing what parts to order for your machine can be a challenge. Our experienced parts technicians are just a phone call away. Saving you from drop ship charges and expediting fees. Messicks stocks nearly 70, different Case and New Holland Parts for the full line of equipment that they offer.
We supplement our own large inventory by making daily pickups from CNH's Mountville, Pennsylvania parts depot. From fuel filters to plow shares, the odds are that Messicks has the parts you need. We're available at or email parts messicks.GM 12-Bolt rear diff UPGRADE: Positraction and gear swap - Hagerty DIY
Keeping your equipment running is what we do best. Messick's parts technicians receive frequent training keeping them on top of changing customer needs.
Can't find what you're looking for? Call our parts hotline at Our parts staff monitor the phones from EST. Parts that we don't have in stock are typically picked up from New Holland's local depot the next business day. In the rare instance parts are not available from these channels we will look to the national parts distribution network, obsolete warehouses, or even the inventory of other dealers.
Our products are all OEM parts unless otherwise noted. Parts Hotline. We're Open - Covid19 Impact. Online Parts. Please enter a search term of at least 3 characters!
Case IH Paint Chart. Case Model Search Enter your model number to find filters, blades, parts diagrams, and more! About Messicks Case Parts Service. Going the extra mile to serve the customer is our company policy. Case Part Number Search. Enter your part number for pictures, pricing, and availability. Case Models. Skid Loaders. Round Balers. Rectangular Balers.
Forage Equipment. Hay Rakes. Rotary Cutters. Manure Spreaders. Tractor Attachments. Soil Prep Equipment. Compact Tractors. Farmall Tractors. David Brown Tractors.