Jeep J-4600 Universal Joint Replacement Guide (1970-1973)
Don't let a bad U-joint leave your classic J-Series truck stranded—here's what you need to know.
- Listen for early warning signs like squeaking at low speeds or clunking when shifting gears to avoid a complete failure.
- Your J-4600 uses 1310 series U-joints for the driveshafts.
- Choose between stronger, maintenance-free non-greasable joints and serviceable greasable joints based on your truck's usage.
- Replacing a failing U-joint is critical maintenance that prevents the driveshaft from detaching and causing severe damage.
Is Your J-4600's Universal Joint Failing?
A U-joint wears out from stress and a lack of lubrication. Because these trucks have worked hard for over 50 years, U-joint failure is a common problem. Ignoring the signs can lead to a disconnected driveshaft, which can cause major damage and leave you stranded. Listen and feel for these symptoms:
- Squeaking Noise: A repetitive squeak or chirp at low speeds (5-10 mph) is often the first sign. This is caused by dry, metal-on-metal contact inside the U-joint's bearing caps.
- Clunking Sound: A distinct "clunk" or "bang" when you shift from park into drive or reverse points to excessive play in a worn U-joint. You might also hear it when you get on or off the gas.
- Vibration: A vibration that you can feel through the floor of the truck, which gets worse at higher speeds, means the U-joint is worn enough to throw the driveshaft out of balance. This can feel similar to an unbalanced tire.
Choosing the Right Aftermarket U-Joint
Original factory U-joints for a J-4600 are no longer made, but the aftermarket offers several good options. The key specification for your truck's driveshafts is the 1310 series U-joint. When choosing a brand, consider this breakdown:
Greasable vs. Non-Greasable U-Joints
You will see options for both "greasable" and "non-greasable" (sealed) U-joints. Non-greasable joints are often considered stronger because the cross is solid metal, not drilled for grease channels. High-quality sealed joints from brands like SKF or Spicer can last a very long time with no maintenance. Greasable joints are a good choice if you do a lot of off-roading through water and mud, as you can flush out contaminants with new grease. However, they must be greased regularly as part of your maintenance routine.
- Premium Tier (Moog, SKF): Moog and SKF are well-known brands with a reputation for quality parts. Moog often includes features like greasable fittings for easy maintenance. SKF's "Brute Force" line is a respected non-greasable option. For a heavy-duty truck like the J-4600, a premium U-joint from one of these brands is a reliable choice.
- Value Tier (GMB): GMB is a Japanese manufacturer known for making good quality bearings and U-joints that often meet or exceed original specifications. They are a solid, budget-friendly choice without sacrificing reliability.
- Jeep Specialist (Omix-Ada): Omix-Ada specializes in parts for Jeep vehicles. Forum discussions show that while some owners use Omix for hard-to-find cosmetic or simple parts, they are sometimes hesitant to use them for critical drivetrain components. They can be a viable option, especially if other brands are not available, but may not have the same reputation for durability as the premium brands.
Aftermarket Universal Joint Cost for 1970-1973 Jeep J-4600
| Item | Price Range |
|---|---|
| New Aftermarket Universal Joint | $18.53 - $39.08 |
| Shop Labor (per driveshaft) | $100 - $250 |
Note: Your truck has multiple U-joints (front and rear driveshafts, front axle shafts). It is common practice to replace all U-joints on a single driveshaft at the same time.
Frequently Asked Questions
How many U-joints does my J-4600 have?
Your truck has at least four U-joints in its driveshafts (two on the rear shaft, two on the front). It also has a U-joint on each front axle shaft behind the steering knuckles, which allows the front wheels to receive power while turning. Some front driveshafts may also have a double-cardan joint near the transfer case, which contains two U-joints and a centering yoke.
Can I replace a U-joint myself?
Yes, this is possible for a DIY mechanic with the right tools. You will need to remove the driveshaft. The main challenge is pressing the old joint out and the new one in without damaging the yokes (the ears on the driveshaft). This usually requires a bench vise, a ball joint press, or a hydraulic press. Rust can make removal difficult.
What does "1310 series" mean?
This is a standard size for universal joints. A 1310 series U-joint has bearing caps that are 1.062 inches in diameter and a width of 3.219 inches from cap to cap. Your 1970-1973 J-4600 uses this size for its driveshafts.
Are there any recalls for the J-4600 U-joint?
No, there are no recalls or technical service bulletins (TSBs) from the NHTSA for the universal joints on the 1970-1973 Jeep J-4600. This is common for vehicles of this age.
Technical Specifications
OEM Part Numbers: 8126614S
Driveshaft U-Joints: 1310 Series (1.062" cap diameter, 3.219" width)
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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.