With or with out grease fittings, a friend told me the grease fitting ones where crap to stick with the sealed ones

 

If you are forgetful and lack maintenance to your jeep, then go with sealed ones.

 

The greasable ones are slightly weaker as they're drilled through. Probably makes no difference for a street-driven XJ though.

 

I prefer the greasable ones. They'll last longer if you maintain them. I've never broken one and I use them in my XJ and my '76 Power Wagon.

 

I also prefer greasable. I'm always messing around under the jeep anyway so might as well check the joints for grease instead of wonder when it'll turn bad on you. Besides, greasing is easy.

 

I like greasable ones too. I got the sealed one cause of the lifetime warranty but after looking at it when I was ready to install I was disappointed it didn't have a greasable nipple. I still used it cause I needed it but when It goes out I'll get a greasable one.

 

We sell both types and see both schools of thought.

If you are the type that has a maintenance schedule firmly planted in your mind and gets under there with a grease gun periodically, I'd consider the ones with the zerk fittings. Otherwise, go with sealed. It only makes sense that the greasable ones will have a tendency to last longer, so long as they actually get lubed. The lubrication with anything that contains moveable parts will only last just so long and then friction takes over. The longer that the part stays lubed, the less friction, therefore it lasts longer. It's basically the same premise that Lucas uses to promote it's oil treatment. The engine sits overnight, the oil drains off of the moving parts. You start the engine, it starts dry until the oil gets pumped up through the galleys. The treatment helps maintain a coating on the parts so no dry starts. Less friction, less wear, longer life span.

It's all pretty much common sense.

And I can't buy the reasoning that because the greasable ones are drilled out that they are inherently weaker. I've never heard of one going bad because the main body of the u-joint failed due to fatigue. They virtually always fail due to wear and/or damage to the roller bearings very often because of worn out lubrication and corrosion that sets in as a result. I can see where your thought might come from, but it just doesn't happen.

 

So you're saying, a piece of metal with a hole drilled in it is stronger than a solid one? Pass the pipe dude. When arguing strength, a sealed one is stronger every time. Any spicer sealed u joint will out last any parts house u joint.

 

No, what I think he is saying is that most u-joint failures are caused by improper lubrication causing excessive friction and wear on the needle bearings. Rarely are they caused by weakened structural integrity caused by a hole in the body or endcap- although I have seen pics of those happening on wheel u-joints.

 

That's because it's says "spicer" on it rather than "china"...
I'm sure they are weaker with the zerk, but how much weaker are they? Enough that it will matter? Have you ever SEEN anyone break a ujoint because of a grease fitting?

 

Yes

 

Sure! I snapped a pair of them in my Corvette half-shafts when the tires hooked. Clean break right along the grease passages. But that is a different animal, not an XJ.
As I previously mentioned, in a street-driven XJ there is probably no difference.
If you do extreme off-roading it is conceivable you could create a shock load sufficient to crack a hollow u-joint, unless there is some other driveline part that is inherently weaker and will sacrifice itself first.

 

I used the sealed ones on mine. Im like having greasable joints. But the sealed on looked stronger thicker and had better seals. I think you can over grease stuff its good to displace moisture but kinda have to wonder every time your greasing something that seals streching and expanding. You dont see em much on modern cars either not saying its a good thing but had over 200k on a ranger and never replaced a u joint.
I can see both sides.

 

With u-joints? no it is not stronger because they see radial forces. With parts like axle shafts? yes because they mostly see a torsion force. Have you ever heard of gun barrel drilling axle shafts?

 

noticed my new to me has the grease able u joints on it. How much grease do I put in it? Like 2-3 pumps from the grease gun or keep doing it till grease runs out or ?