Jeep Gladiator & J-Series Truck Universal Joint Replacement Guide (1971-1975)
Keep your classic Jeep's driveline reliable by understanding how to choose the right U-joints.
- Listen for clunks, squeaks, and vibrations, which are the primary signs of U-joint failure.
- Always measure your old U-joints before ordering; 1310 series is common for driveshafts, but variations exist.
- Choose high-quality aftermarket brands like Spicer or Moog for long-term reliability.
- A non-greasable, solid-body U-joint from a premium brand is often stronger than a greasable one.
Symptoms of a Failing Universal Joint
A worn-out U-joint is not something to ignore. The most common sign is a new noise coming from under the truck. You might hear a squeaking sound at low speeds that changes with your speed. Another classic symptom is a loud "clunk" or ringing sound when you shift from drive to reverse or vice-versa. As the U-joint wears further, it can cause a vibration that you feel throughout the truck, which gets worse as you drive faster. For the front axle U-joints, you might hear a clicking noise or feel a bind in the steering when making sharp turns at low speed.
Choosing the Right Aftermarket U-Joint
For a vehicle from the 1970s, finding original equipment (OEM) parts from a dealer is nearly impossible. The good news is that high-quality aftermarket U-joints are readily available and often meet or exceed the original specifications. The key is to choose a reputable brand and, most importantly, to get the right size.
Measure Before You Buy
The 1971-1975 Jeep trucks used different axle and driveshaft combinations. The most common driveshaft U-joint is the 1310 series. Many 4x4 models used a Dana 44 front axle, which takes a specific axle U-joint (often a Spicer 5-760x). The only way to be certain is to remove and measure your old U-joints. You will need a caliper to measure the cap diameter and the overall width of the joint.
Brand Quality Tiers
- Top Tier (OEM Quality): Brands like Spicer are the gold standard. Dana-Spicer was the original manufacturer for many Jeep components, so their parts are considered an exact match for quality and fit. Many experienced mechanics prefer Spicer's non-greasable "Spicer Life Series" (SPL) joints because the solid cross design is stronger than a joint drilled for a grease zerk.
- Quality Aftermarket: Brands like MOOG offer reliable, quality U-joints that are a popular choice for replacements. They often feature grease fittings, which allow for periodic maintenance to flush out contaminants.
- Standard/Economy: Cheaper, unbranded "white box" parts are available. While the low price is tempting, these often use lower-quality materials and can have manufacturing defects, leading to premature failure and the need to do the job all over again.
Greasable vs. Non-Greasable
A non-greasable U-joint (like many from Spicer) is forged from solid steel, making it stronger. They are pre-filled with a specific amount of high-quality grease and sealed for life. A greasable U-joint has channels drilled through it for a grease fitting (zerk), which can make it slightly weaker. However, the ability to add fresh grease periodically can extend its life, especially if the truck is used in muddy or wet conditions.
Common Ordering Mistakes & Known Issues
- Incorrect Size: The biggest mistake is ordering the wrong size. Do not assume all U-joints on your truck are the same. The front axle U-joints are different from the driveshaft U-joints.
- Double Cardan Joint: Some front driveshafts have a special two-joint assembly called a double cardan joint near the transfer case. Rebuilding this requires a specific centering yoke kit in addition to the U-joints.
- Recalls/TSBs: There are no known recalls or Technical Service Bulletins (TSBs) from the NHTSA for universal joints on the 1971-1975 Jeep Gladiator or J-Series trucks. This is a standard wear-and-tear item.
Frequently Asked Questions (FAQ)
How many U-joints does my 1971-1975 Jeep truck have?
A typical 4x4 model has a total of five: one at each end of the rear driveshaft (2), one at the front of the front driveshaft and two in the double cardan joint at the rear of the front driveshaft (3), and one in each front axle shaft at the wheels (2). However, configurations can vary. Always inspect your specific vehicle to confirm.
Should I replace all the U-joints at once?
If one U-joint has failed due to age and mileage, the others are likely not far behind. It is good practice to replace them all at the same time, especially the ones on the same driveshaft, to ensure a balanced and vibration-free driveline.
Can I replace a U-joint myself?
Yes, if you have the right tools and some mechanical experience. You will need a good set of sockets, snap ring pliers, and either a bench vise or a U-joint press to push the old joints out and press the new ones in. It can be a difficult job if the parts are rusted together.
What is the difference between an axle U-joint and a driveshaft U-joint?
While they perform a similar function, they are different sizes and designs. Driveshaft U-joints typically use external snap rings to hold the caps in the yoke. Front axle U-joints are held in by internal "C" clips and are designed to handle the stresses of both powering and steering the front wheels.
Technical Specifications
Common Driveshaft U-Joint: 1310 Series (Cap Diameter: 1.062 in, Width: 3.219 in). Common Dana 44 Front Axle U-Joint: Spicer 5-760x (Cap Diameter: 1.188 in, Width: 2.188 in). Note: These are common sizes, but you must measure your specific parts to confirm fitment.
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.