U – Joints & Driveline

1. U – Joint Body or Cross
2. Trunnion
3. C-Clip
4. Bearing Cap
5. Needle Bearings (Located inside of Bearing Cap)

Operating Angles:

Standard U – Joints aren’t designed to run at extreme driveshaft angles unless they are specially constructed. As a rule of thumb, the angle of a driveshaft should not exceed 22degrees. However, some manufacturers do make quality high-angle driveshaft’s that operate dependably from 22 to 80 degrees. Extreme-angle driveshaftsare achieved by using a “Double Cardan” constant velocity joint. This is basically a joint with two u-joints.

This table is based upon the joint at rated load and life. Going above the rated load or angle will decrease the u – joints life. As a general rule of thumb, for each doubling of the operating angle, RPM, or load, the lifetime of the joint is decreased by half. Rated lifetimes are on the order of 3000hours.

In the typical off – road vehicle, a suspension lift is done to increase clearance and allow larger tires to be installed. To compensate for the larger diameter, lower gears are installed in the axles. The lift increases the angle of the shaft and the lower gears means the shaft has to spin faster for a given axle speed; both things are working in the wrong direction on this chart. No wonder, driveshaft problems are common in vehicles modified for off-road use.

Most Common Series U – Joints For Off Road

1310 (also 297X): – The 1310 (shown) is a 1/2 ton u – joint used in driveshafts for many Jeep applications and is retained via external snap rings; the ones that slightly resemble a pretzel. The 297X u – joint is effectively the same size but with intern al snap rings used for steering knuckle joints on most Dana 44 and Corporate 10 bolt front axles.

1330 – This is a 3/4 ton driveshaft u – joint most often found at the pinion yoke going int o Dana 60 front or rear axles. The 1330 shares the same cap size as the 1310 but with a larger cross.

1350 – Most 1 ton trucks of yester – year used these joints (middle joint in picture) in their driveshafts but could be found in 3/4 ton and 1/2 tons occasionally. Note the cross is the same size as the 1330 to its left but the bearing caps, and therefore the “Trunnion” that they pivot on are larger, i.e. more strength.

1410 – In recent year s, the Super Duty line from Ford, and Chevy and Dodge H.D. series are using even beefi er joints in their driveshafts. The 1410 can be consider ed a 1.25 ton joint and is appropriate when behind the torque mons ter diesel engines from the Big Three.

1480 – his joint (farthest right) is most commonly a steering knuckle joint rather than a driveshaft u – joint and resides inside the knuckles of Dana 60 and 70 front axles. In a driveshaft application, it could be considered as a 2 ton joint . Keep in mind that a steering knuckle joint sees 3 – 5 times as much torque as the driveshaft joints strictly from the ring and pinion reduction. It is further multiplied by having the steering turned to anything other than straight.

297X vs 760X – Spicer phased out the old dependable 297X u-joint and replaced it with the new 760X. Shown is a new Spicer 5-760X cross and bearing kit next to the old 5-297X. These joints are an updated design and have a cold-forged cross which has repeatedly been shown to be much stronger than the 297’s hot-forged cross, with a much longer fatigue life. This should help to further put the brakes on broken u-joints.

The bearing caps of the U-Joint are pressed into the Yoke and held in place with a C-Clip, an Internal Snap Ring, or a Full Circle Snap Ring. Vehicles that see heavy off-road use should use an internal or full circle snap ring. If C-Clip style u-joints are only available for your application, you can have them modified to accept full circle clips.

When pushed real hard with locking differentials & oversized tires, the joint’s bearing caps often will try to ‘spin’ in the yoke as the joint operates. As it rotates, it often “spits” off u-joint c-clips and then the cap is free to walk out of the yoke, departing from the axle (if it doesn’t get crushed by the Balljoint Stud first). The U-Joint trunnion then rips apart the axle yokes, causing a catastrophic failure. Even if it doesn’t break the yoke, it will still stretch them out so they won’t properly hold the cap anymore.

Notes:

1) Lube Fitting In Bearing Cap
2) Mercruiser Kit
3) Used In Closed End, Spicer Front Axle

U-Joint Cross Reference:
Are all the numbers confusing you? 1310 series, 1350 series and so forth? Here’s a sizing chart. Or simply contact Niagara Drivetrain at – info@niagaradrivetrain.com or call us at 905-641-5464
“Your one stop Driveline Shop in the Niagara Region”
Niagara Drivetrain Centre Limited
620 Welland Avenue Unit 626-628
St. Catharines, ON
L2M 5V6

Driveline Parts and Components List and Brand Names Available At Niagara Drivetrain Centre Limited