426 Wedge

Just Picked up a AU driveshaft. I noticed when I repacked the u joint cups that 2 of them seem to have a rough spot when spinning. ( Don't think thats too good). Would I want to replace it with a non greasable or a grease type ujoint?

sofakingdom

iTrader: (1)

Maybe....

That would depend on the cause of the "rough spot".

The needle rollers in a U-joint are basically impossible to test by hand; if the trunnion looked OK when you cleaned it up before you greased it, then it's OK.

Usually a "rough spot" has to do with the grease seal.

In case you decide to replace it with a non greasable or a grease type ujoint, make sure you get the part # that's specifically designed for the aluminum drive shaft. There's no "strength" or fitment difference, but there IS a treatment of some sort to prevent dissimilar-metal electrolysis and corrosion.

People talk about the non-greaseable ones being "stronger". I guess they are, maybe slightly, just because they're not drilled for the grease. IMO it's hair-splitting. I'd prefer to be able to squirt some new grease in em once in a while, if I get a wild hair or whatever. Maybe every 50,000 miles or so. They'll last the life of a car (300,000 - 350,000 miles) if you keep em lubed, and they're not dramatically overloaded or otherwise abused.

//<86TA>\\

iTrader: (14)

ive heard that the strenght issues stem from the needle bearings, or size of the needle bearings. Some cheaper brands of u-joint use larger needle bearings, thus reducing the diameter of the shaft( i dont know what its called) others have the same sized needles as the solid u-joints. I ran into this when i replaced the u-joints on my driveshaft.

greezemonkey

iTrader: (14)

factory ones have always been non greaseable, I would not use a greaser if it were given to me period, changed out way to many aftermarket greaseables in my 23 yrs as a mechanic..spicer is the best u joint, a good one should run around 25$ the aluminum driveshaft ujoint is different than it`s steel conterpart, they do not interchange.

426 Wedge

I did notice inside the trunion what appeared to be discoloration of the metal. A pattern apperared, vertical lines. like the needle bearings got real hot. And maybe when the car was parked the hot needles cooled, caused the pattern??

I will swap the seals and see if the rough spot follows the seals.

sofakingdom

iTrader: (1)

That makes NO SENSE WHATSOEVER.

Think about it..... factory U-joints are non-greasable. If that's so much better than greasable ones, then why did the aftermarket ones come to be installed in all those shafts in the first place? And out of ALL the aftermarket greasable U-joints that have been installed in the history of the world, what proportion have failed? More, less, or the same, compared to non-greasable ones? I'm not the betting kind; but if I was, I'd bet that it's FEWER, simply because some small part of them got a shot of grease once in a while. So how is a non-greasable better? Now I'm pretty stupid and all, in fact I will FREELY admit that I'm a complete idiot and moron; but I fail to see how a U-joint that can't be lubed without destroying it, or AT BEST requires all manner of disassembly to lube it and therefore never gets lubed anyway, is superior to one that you can shoot new grease into once in a while. All else being equal of course, which it easily can be. Pretty much all of the mfrs make ones that are both greasable and not, and they are the same except for being cross-drilled and drilled for the zerk. Same trunnion forging, same needles, same caps.

It is definitely true that a U-joint with many small needles is better than ones with fewer large ones. Not only is there the diameter issue (trivial IMO, but still there); but also, if there were say twice as many rollers, then there would be twice as many contact points, and therefore half as much force at each.

Dana/Spicer is a good brand; so is Neapco, and BW, and some others. For a street car though, it hardly matters, as long as you get a greasable one and KEEP IT GREASED.

The way U-joints fail, is that when they run dry (out of grease....) the needles make little imprints on the trunnion at the places where they always run (which is why drive shafts are ALWAYS supposed to have a slight angle... so that the U-joints roll a little bit and don't just sit in the same place all the time). If the trunnion is no longer smooth and round and uniform-looking, then yes, it's used up and should be replaced. It has nothing to do with heat and parking and cooling, it's just wear.

Apeiron

A correctly installed greased joint would be close enough to the strength of a solid joint that you wouldn't care about the difference. An incorrectly installed one would be a different matter.

greezemonkey

iTrader: (14)

I see where your coming from and I can understand your reasoning, my experince with aftermarket u joints that are greaseable...they fail because no one greases them..you are right, BUT...a true non greaseable joint has synthetic grease so it won`t break down like mineral grease AND it is 100 and 50 percent SEALED...no water intrusion..that is why my friend they always last 100,00 miles or longer where as your 7$ greaser joint is not even close to being protected from the enviroment due to lower quality cap seals that do not seal 100%...Plus we all know excluding people like ourselves, NO ONE greases them, not your typical owner nor your average 10 min lube tech at least around here. If you you grease them at every oil change they would last just as long I would think but I have not seen one yet with that mileage.

sofakingdom

iTrader: (1)

I'm not talking about $7 "made in India" or whatever U-joints, that happen to include a grease fitting. The difference between a crap U-joint and a good U-joint is one thing, the difference between a greasable one and a non-greasable one is something else entirely.

I'm talking about the difference between greasable and non-greasable ones.

I can walk into the parts store and order up a U-joint from Dana, Neapco, or BW, and specify greasable or not. They are identical in every way except that one has been drilled & zerked and one has not. They even cost about the same, maybe $1 different. They have the same trunnion, the same caps, the same needles, the same seals, and the same grease already installed in them.

All U-joints, greasable or not, are sealed. No water (or much of anything else....) intrusion. A quality brand's seals seal just as well whether the trunnion has been drilled and zerked, or not.

I'll DEFINITLEY agree with you however, that cheeep crappy offshore inferior U-joints, greasable or not, are inferior to quality ones, greasable or not.

However, the feature(s) that make them inferior and crappy, IS/ARE NOT the fact that they're greasable (or not).

In other words, a crappy non-greasable U-joint is just as crappy as a crappy greasable one. Just the same as a quality greasable one is just as quality as a non-greasable one.

Frankly, I'd rather at least have some kind of outside chance or at least the outside possibility that someone, somehow, sometime, along the life of a U-joint, will accidentally screw up and grease it. I fail to see how rendering that impossible makes one of them any better.

greezemonkey

iTrader: (14)

After just recently touring an Arvin Meritor plant we had a chance to speak with a Spicer/Dana rep, in his office was on display several HD truck U joints, one had 1.5 million miles and to be honest looked like it would go another mil, no grease fitting, in fact none of the examples new or used on display had a fitting. Talk to a rep of the best u joint made Spicer and then ask him what IS the best u joint and then ask if you can grease it. Just stating a point from 23 years of experince as an auto tech...you can only get that one day at a time.

sofakingdom

iTrader: (1)

Where somebody takes them apart from time to time and GREASES them, like EVERY OTHER PART of a truck....

Which doesn't happen in a car. Has nothing to do with the issue at hand.

Which means, you put a non-greasable U-joint in a car, and you start a timer: the U-joint has xxx miles, days, revs, or however you want to measure it, to live.

Which also means, you put a QUALITY greasable one in, you start the same timer; the timer runs out at the same time; then YOU CAN PUT IN MORE GREASE, EASILY and without disassembling anything, and reset the timer to ZERO and start all over again. Whether people DO put in more grease or not, on average, is an open question; but no one has lost ANYTHING by using a greasable one.

What was the benefit of a non-greasable U-joint again? I'm having trouble remembering... I'm only speaking from about 35 years of experience, and as we all know, your memory is the second thing you lose when you get old, but I forgot what the first one was.... although one of the girls at work told me once I should ask my wife and maybe she would remember it, but maybe not, she's getting old too...

Guest

Well as was already stated quite clearly, the seals arent any different between the ones with the fitting and the ones without. So the amount of actual grease between either version is going to be the same over time. I sold that stuff for many years and as already stated, the only difference was the fitting and a slight change to the casting where the fitting is located. We also had a machine shop, I lost count how many non-greasable u-joints I removed from GM driveshafts alone. All the failed ones were dry. So blame the right thing, lack of lube and/or lack of keeping the lube in the joint.

gmgod

Are the federal mogul/precision u-joints any good?

I've got a set of em that I've been meaning to install for the last couple years or so, can't remember what I paid for em. Does anyone know if these are the cheapies that you want to avoid??????? They say made in USA.

Apeiron

Precision is fine.

Guest

Precision is good stuff. They also have HD joints available if you want those.

sofakingdom

iTrader: (1)

Agreed... they're as good as any of those others we've been talking about.