Understanding Spicer Universal Joints: Types and Applications

Universal joints, commonly known as U-joints, play a crucial role in transmitting power from the engine and transmission to the axles in vehicles. They connect rigid shafts whose axes are inclined to each other. This article explores the various types of Spicer universal joints and their applications, with a focus on their design, features, and performance characteristics.

The Fundamentals of Universal Joints

A universal joint (also called a universal coupling or U-joint) is a joint or coupling connecting rigid shafts whose axes are inclined to each other. It is commonly used in shafts that transmit rotary motion. It consists of a pair of hinges located close together, oriented at 90° to each other, connected by a cross shaft.

The main concept of the universal joint is based on the design of gimbals, which have been in use since antiquity. The first recorded use of the term 'universal joint' for this device was by Hooke in 1676, in his book Helioscopes.

Types of Spicer Universal Joints

Spicer offers a comprehensive range of universal joints designed to meet the diverse needs of various vehicles and applications. These include:

Spicer Life Series® (SPL®) U-Joints

Spicer Life Series® (SPL®) universal joints deliver high performance and are engineered to ensure peak performance. These u-joints consistently outperform competitors, so you can hit the road or trail with confidence. They are designed to withstand the increased stress that high-efficiency truck configurations place on the driveline.

Features of SPL® U-Joints:

Cold-Forged Steel: Spicer Life Series® (SPL®) universal joints are cold-forged from high-quality steel, delivering the strength and durability that today’s performance vehicles demand.
Greaseable and Non-Greasable Options: SPL® u-joints are available in both greaseable and non-greaseable options. Both offer unparalleled performance.
Synthetic Thrust Washer: For optimal friction reduction and higher temperature resistance.
Multi-Lip Seal: Keeps grease in-and contaminants out, offering maximum retention in a wider range of environments. This premium sealing package includes a Viton® multi-lip seal, garter spring, seal guard, and a needle bearing spacer.
Journal Cross: Engineered with a solid cold-formed body to ensure better wear and overall strength.
Bearing Cups: Heat-treated for strength; precision-ground and case-hardened for durability.
Thrust Washers: Eliminate metal-to-metal contact, prevent wear and lower the overall operating temperature.

Spicer Extreme U-Joints

Spicer Extreme u-joints are the ultimate solution for extreme off-road enthusiasts who push their vehicles to the edge and beyond.

Features of Spicer Extreme U-Joints:

Full Circle Snap Rings: The Spicer Extreme u-joints include full circle snap rings, which nearly eliminate the possibility of the rings being ejected under load.
Needleless Bearing Caps: The needleless bearing caps are sealed with an internal O-ring and come with a high-grade anti-seize lubricant. The caps also have provisions for grease fittings.
Increased Load Capacity: The increased load capacity of the Spicer Extreme u-joints makes it ideal for pairing with chromoly axle shafts with full circle snap rings.

Spicer 10 Series U-Joints

When it comes to torsional fatigue capability, the competition can’t touch the Spicer® 10 Series u-joint. These u-joints are consistently stronger, helping to ensure longer life and better performance. Zerks are positioned at 180°, so lubrication can be done without rotating the driveshaft.

Applications of Spicer Universal Joints

Spicer universal joints find applications in a wide array of vehicles and industries, including:

Passenger Cars and Light Trucks: Used in rear-wheel-drive vehicles to transmit power from the transmission to the rear axle, accommodating driveline angles and suspension movement.
Commercial Vehicles: Engineered to ensure peak performance in high-efficiency trucks, withstanding increased stress on the driveline.
Off-Road Vehicles: Spicer Extreme u-joints are specifically designed for off-road use, providing the strength and durability needed for challenging terrains.
Industrial Applications: Utilized in various industrial machinery and equipment where rotary motion needs to be transmitted between inclined shafts.

Understanding U-Joint Sizing

Using the correctly sized u-joint in your driveline is critical for proper fitment of your driveshaft to prevent vibration, breakage, and even possible ejection of your driveshaft! There are two measurements you will need to make/confirm to determine the correct u-joint for your application. These measurements are the overall width of the u-joint assembly (from cap to cap) and the cap’s diameter. These two measurements will help confirm what series of u-joints you have using our u-joint chart so you can obtain the proper replacement u-joints. Note that you can have a u-joint with two different bearing cap sizes. These types of u-joints, commonly referred to as conversion or combination u-joints, usually can be had as a U-joint 1310 to 1330 or U-joint 1330 to 1350 pairing of bearing caps to aid in driveline conversions. In some instances, the use of a U-joint 1310 to 1350 may be called for. This special U-joint 1310 to 1350 can solve mix and match driveline issues. This is important to remember and is why we recommend always measuring a bearing cap off each “cross” of the u-joint for proper u-joint identification, as the difference between a bearing cap for a 1310 u-joint vs 1350 bearing cap is only 1/8-inch (.125”). The use of calipers or a micrometer is highly recommended for accurate measurements. When we are discussing the various bearing cap sizes of a u-joint it is important to note that the measurements between the different u-joint cap sizes are minimal and can be tough to confirm with a tape measure or ruler, which is why we recommend a set of calipers for precise measurements that are easy to confirm.

Common U-Joint Series: 1310, 1330, and 1350

While there are other series of u-joints within the driveline components industry, the three most common u-joint by size for passenger cars and light trucks are the 1310, 1330 U-joint, and 1350 U-joint types. These types of u-joints are comprised of a specific body dimension and cap diameter and must be used with the matching driveline flanges/yokes for proper and safe operation. Most factory u-joints up until the mid-1970s were of the 1310 series, so with performance upgrades that provide more power, and more importantly more torque, to the driveline an upgrade to 1330 or 1350 series u-joints should really be considered. As the u-joint series moves up in size you’ll see that only certain aspects of the dimensions change. However, these changes net a significant increase in torque capabilities. When it comes to 1310 vs 1330 u-joint, the 1310 and 1330 joints share the same cap diameter, but the 1330 has a larger body. Meanwhile, the 1330 and 1350 u-joint have the same body dimensions, but the 1350 uses a larger cap diameter. It’s easy to see that the 1350 u-joint hp rating would be the highest, but in the real world you may not need the capabilities of a 1350 series u-joint. Determining the proper u-joint for your needs will include factors such as horsepower, tire diameter, tire compound or “stickiness,” gear ratio, and vehicle weight.

Greasable vs. Sealed U-Joints

For most any application you will find both a greasable and a solid or sealed U-joint option. When it comes to greasable vs sealed U-joints, there are some considerations you must factor into your driveline’s U-joint needs, including accessibility, use case, strength needs, and more. For example, if you’re building a nice street cruiser that will rarely see rain and isn’t being launched hard on slicks or drag radials, you could easily use a greasable U-joint, provided you incorporate greasing the joints into your regular chassis maintenance. Alternatively, consider that when it comes to greasable vs solid U-joints that a solid U-joint may be the better solution. This is especially true for higher horsepower applications, or you’re looking for a maintenance free solution. The solid body of a non-greasable U-joint is stronger, as it does not have the cross-drilled grease passages of the greasable version. These drilled passages take away material and overall strength, no matter the U-joint size. Your use case will also determine greasable vs solid U-joints and what is best for you. Building an off-road rig that’s going to see lots of mud and water up to the wheel hubs?

Maintaining and Replacing U-Joints

When u-joints go bad you’ll typically have a squeak coming from the driveline at first (indicative of dry needle bearings) which often turns into driveline vibration, and ultimately u-joint failure. The best course of action is to service your u-joints regularly (if greaseable) or replace them at the first sign of noise.

U-Joint Replacement Procedure

When it comes time to replace your driveshaft’s u-joints the job is not difficult, though it does take a couple of extra hands, a press, large C-clamp, or a vice, and suitable work area to support the length of the driveshaft. Using a drive shaft u-joint diagram will help in keeping all the parts going back together correctly. A press or large vice works best, but you can always use the hammer and socket method of extracting a u-joint. In preparation for u-joint replacement it is best to mark your driveshaft yokes to the trans slip yoke and differential pinion yoke to ensure everything is reassembled in the same manner. To remove your worn u-joints the snap rings must be removed with the appropriate snap ring pliers first. Often, a quick smack with a hammer on the yoke itself or with an old socket or proper diameter steel shaft directly on the snap ring face will help to unstick the snap ring in the groove, allowing it to become free enough to be removed with snap ring pliers. Once the snap rings are removed the u-joint can be pressed through the yoke until the opposite bearing cap is free to be removed by hand.

To install your new U-joint, carefully remove the bearing caps and place the bare u-joint body into the yoke and all the way to one side. This will allow you to reinstall that side’s bearing cap over the u-joint’s trunnion (the machined surface the bearing cap and needle bearings ride on) and then use a press or vice to apply pressure to the bearing cap until seated below the snap ring groove. You want to do this carefully to not unseat any of the needle bearings. Install the new snap ring supplied.

U-Joint Lubrication

While many OEM types of u-joints are sealed, and often it is preferable to use a non-greaseable, solid body u-joint for its extra strength, for many street going vehicles a u-joint with grease fitting is perfectly acceptable and will last a long time with proper servicing. Access to the u-joint’s grease fitting can be hindered by the driveshaft yoke at certain ride heights. Often simply moving the rear suspension up and down while the vehicle is on jack stands will provide enough clearance to insert a grease gun tip into the location. For greaseable types of u-joints it is preferred to flush the old grease and contaminants out by injecting new grease into the u-joint grease fitting until you see the new, clean grease exiting all four bearing caps at the seal area. Pump the grease gun slowly to not damage the seals and do not use a battery or air powered grease gun for this operation. Once all four bearing caps show new grease being pushed past the seals you can wipe away the old/extra grease and clean the u-joint of any exterior dirt and grease. As mentioned above, for greaseable types of u-joints the small bit of maintenance required pays off in longer life of the u-joint. Using a manual u-joint grease gun works best for filling/flushing the u-joint’s grease.

tags: #spicer #universal #joints #types #and #applications