Part 4 - U-joint tech

Choosing U-joints

When it comes to universal joints of a given size or series, there are 2 decisions to make - which brand to choose, and which style (permanently sealed or re lubable)

The first decision is simple in my opinion. Spicer Life Series no question. I believe they are simply the best. Why? I'll let them explain it (below):

Why should you use Spicer U-joints?

According to Spicer:

Spicer has been the leader in cardan universal joint technology since 1904, when Clarence Spicer patented the first practical application of a universal joint to replace the chain drives of his day. Since that time, we have refined our universal joints with improved forging technology, metallurgical studies, hardening processes and sealing capabilities to ensure greater durability and low maintenance.

Spicer engineers research and implement advanced hot and cold metal forming processes for journal crosses, heat treating methods for case hardening bearing cups, finite element analysis and three-dimensional modeling to understand and control stress points, and perform myriad laboratory and application tests to validate joint performance. We sweat the details so all of our cardan joints provide you with longer, trouble-free service.

There are 2 different models to choose from - the Spicer Time-Tempered™ and the Spicer Life™. Both are described below. As you will see, the only choice for us is the Spicer Life™ series.

Spicer Time-Tempered™ Replacement Cardan Universal Joints*

This OE-acceptable replacement u-joint kit has a hot-forged steel journal cross that is heat treated and through drilled for grease channels. It is equipped with a grease fitting for ease of re lubrication. Journal cross trunnions are hardened for long life, and the faces are grooved to ensure consistent lubrication of the needle roller bearings.

The Spicer Time-Tempered replacement cardan u-joint's distinctive blue rubber seals provide grease retention within the bearing assembly while protecting it from contaminants and are designed to purge grease upon re lubrication.

Spicer Life™ Original Equipment (OE) Cardan Universal Joints

The newest cardan universal joint in the Spicer product line offers advanced design features for longer life and superior performance. Bearing cups are case hardened through a carburizing heat treat process, and the inside diameter and thrust washer surface are machined to the highest tolerances of all Spicer bearing assemblies. The journal cross is cold-formed for added strength, and trunnions are machined to give the best possible surface for the needle roller bearings.

Spicer Life OE cardan universal joints stand above the rest for the tough, worry-free performance demanded by today's discriminating consumer and are the preferred choice of many automotive design engineers for passenger cars, pickup trucks and sport utility vehicles. They also have proven performance and are used extensively by professional motor sport teams in IROC, NASCAR and NHRA.

Features include:

Cold-Formed Journal Cross
Cold-formed for increased strength, the journal cross is not through drilled with grease channels, but rather partially drilled to increase strength and retain the appropriate amount of premium, lithium-based grease for maintenance-free operation.
Thermo-Plastic Seal Guard
Helps prevent contamination in the bearing assembly and secures the bearing onto the trunnion of the journal cross.

Triple-Lip Seal
Enhances grease retention and prevents contamination in the bearing assembly by utilizing three lips instead of two.
Composite Thrust Washer
Spicer Life series u joints feature a thermoplastic thrust washer in the bearing cup. This Eliminates metal-to-metal contact between the trunnion end and bearing cup. Prevents wear and end galling, and lowers the overall operating temperature of the universal joint.

To lube or not to lube

So the only remaining question is - do I use permanently sealed u-joints or re lubable u-joints (assuming there is a choice in the size/series you are using)

This is not so simple to answer, and has long been the topic of many fierce debates. It may well come down to personal preference, but there are some points to consider.

Most importantly - relubable u-joints MUST BE re lubed. It sounds obvious, but the one thing you do not want to do, is to kid yourself that you will do regular routine maintenance on your driveshaft and u-joints, and the not. And yet, this is exactly what a HUGE number of people do. Avoid it. Be honest with yourself. If you aren;t going to re lube them - use the "permanently" sealed kind, if not, you will experience premature failure.

So, we have to be brutally honest with ourselves, fine. But what if we are the kind that actually would re lube the joints EACH and EVERY time they require it, properly, completely (see Part 3), and without fail (am I making a point here? There aren;t many people who fit into this category). Is there then any reason to prefer on kind over the other? You have to decide for yourself, but some advantages and disadvantages to consider are:

Re-lubable

• (-) They have to be religiously re-lubed, a PITA
• (-) They generally are not as strong, due to the grease channels in the cross
• (-) If you lose or break a grease zerk (not uncommon) the joint is useless (you could just replace it, but it it's been out for a while, way more contaminant will have ingressed into the joint than can even be flushed out by proper lubrication
• (-) Slightly more of a pin to install, as you have to get the grease zerks in the right place and all lined up
• (+) They are generally cheaper
• (+) Depending on environment, they may last longer (if conditions are wet and muddy, the ability to purge the joint and relubricate it, may well extend the life of the joint beyond that of a joint that cannot be relubricated. However, in dry condition, this will likely be much less of a factor.

Sealed

• (-) Depending on environment, may have a reduced service life than a relubable, since nothing is ever really 100% sealed, so that if contaminants do get in, there is no way to flush them out
• (-) More expensive
• (-) A bit more of a PITA to install, as you have to make sure you have sufficient lubricant in the caps before you install the joint, since you cannot add any afterwards.
• (+) Stronger, due to absence of through-cross grease channels
• (+) Less to worry about - don't require any maintenance.

Personally, I choose to run Spicer Life Series permanently sealed (NON-relubable) u-joints in my 1350 CV driveshaft, for the following reason: With my type of rig and the wheeling it does, the fact that it's a trailer queen, sees very little high speed use, sees very little total mileage in a year, and yet must be as strong and reliable as possible - I need to squeak every little bit of strength I can from every component, and things are much more likely to break catastrophically way before their time, rather than wear to due to a lack of lube.

Causes, Analysis, and remedies for Driveshaft failure

Causes and remedies of driveshaft vibration include:

• Improper universal joint operating angles / improper driveshaft geometry
  • Measure and set proper geometry (see Part 2)
• Too extreme universal joint operating angles
  • Switch to higher angle capable u-joint series or CV joint
  • Reduce operating angles (usual. by reducing suspension height)
• Poor balance of driveshaft assembly
  • Have driveshaft professionally balanced
• Driveshaft balance weights damaged or missing
  • Have driveshaft professionally balanced
• Worn-out / improperly lubricated U-joints
  • Inspect, lubricate, replace u-joints as required
• Worn tail-cone / slip yoke or slip member
  • Inspect and replace worn components as required
• Bent, dented, fractured tubing
  • Inspect and repair/replace as required

Driveshaft Failure analysis Guide

Yokes

Universal Joints

Tubing

Spicer Stock Driveshaft Applications and Info

Click HERE for a .pdf file of late model OEM Spicer Driveshaft listings

Spicer driveshaft parts catalogues

• Spicer center yokes tube yokes and ball stud tube yokes
• Spicer Companion Flanges
• Spicer Double cardan CV joint assemblies
• Spicer End Yokes
• Spicer Flange Yokes
• Spicer Small Parts
• Spicer Tube Shafts
• Spicer Yoke Shafts

Spicer part number de-code information

Spicer Part Names and Symbol Numbers

Spicer brochures

Spicer Life™ light vehicle U-joint brochure

Spicer Driveshaft Training Videos

Proper universal joint lube path (50MB)

Measuring Driveshaft slopes and operating angles (35MB)