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Possibly 2x Pump of Moly Grease into U-Joint...Am I Screwed?

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34K views 24 replies 12 participants last post by  FJtest  
#1 ·
Hello all...I bought my 2012 FJ on Wednesday and after reading this forum almost all day I was excited to go home and make sure my driveshaft was lubed, since it sounds like it's hit or miss if most shops perform that easy yet critical job.

I had purchased a general automotive grease (#2 NGLI lithium), and one that claimed to be moly-fortified in the description on Amazon ( see here ). My plan was, as prescribed, to use the moly-fort in the slip yoke, and the "general" #2 NGLI lithium in the U-Joint. Well, long story short, if you look at the PHOTO on the link I posted for the moly-fortified, it specifically says, "for universal joint" on the tube. I loaded it in my grease gun and greased all 4 universal joints without a second thought. When I went to load what I assumed was the moly-fortified into my other grease gun, I realized that THAT was the "general" grease.

I think there's about a 50% probability that the amazon description is wrong. The tube SPECIFICALLY says for use in universal joints, and the tube ITSELF does not say anything about moly on it.

JUST IN CASE it actually IS moly-fortified, what should I do? It only took 2 pumps (more like 1.5) before there was a little grease coming out of the u-joint, so it's not like I blasted the thing full of molybdenum. On the other hand, if moly really does cause premature wear of the bearings in the u-joint, I feel I might want to do something about it...but what? Get a non-moly grease and REALLY pump it through there? Or is 1-2 pumps dilute enough that I should be alright?
 
#2 ·
Long story short.
Moly is designed for frictional surfaces like slip yoke or in other words extreme pressure, metal to metal surfaces. It is not designed for any type of “high speed bearings”.

Now that the “U” joints are contaminated with Moly you have 2 choices

1 to change out the U joint which can be costly.

Or you can push the moly out by injecting fresh grease.

If you follow this procedure you should be fine.

Drive the truck for “5” minutes only than pull into your garage and pump in fresh grease till you can see the old grease getting pushed out of the seals and repeat it “10” times.

The reason I say 10 Times is, you want to make sure there is nothing left in there.

Here is a pic of my 1351 Fj U joint.
Part# 04371-60070

You can also see the grove that is Machined on the spider and that’s how the grease will get pushed into the cups and in between the rollers.

Moly can cause excessive amount of “HEAT” if left in any bearings and it will destroy it in no time.
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#3 ·
Great pictures and thanks for the response!

I'm wondering then why Valvoline marks their product "for Universal Joints". Is it possible that the concentration of moly is incredibly small? Also, do you think the 2x pump I put into the joint is enough that I should be worried? I've gotten mixed information from the different sources I've seen. I understand that moly-fortified grease is NOT ideal, and I will never use it again...but will the small quantity that I put in make a significant difference?
 
#4 ·
I worked at a couple dealers in a past life and the techs only had one lube gun. It was usually lithium w/3% moly. I personally have 100,000s of miles on 3% moly in my ujoints in various toyota trucks/4runners.

Call your dealer/service manager and I bet they dont use anything but 3% and have no idea that Toyota specs different greases on the dshaft.

here is some talk about it from the 4rnr forum:

Drive/Prop Shaft Greasing Guide - Toyota 4Runner Forum - Largest 4Runner Forum
 
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#5 · (Edited)
Thanks sloth. I actually took the FJ in to get a couple outstanding recalls wrapped up today and asked the SA what he thought. He told me that it wasn't enough to matter...on the other hand this is the same dealer who underfilled the AT in my Tacoma so.........perhaps I'll squeeze out the old grease.

I stopped by O'Reilly on the way home and noticed they made a Lucas Oil "X-Tra Heavy Duty" grease (it's green) for high speed bearings. It is #2 NLGI and does not mention containing Moly on the tube...but as I learned from my Valvoline experience that doesn't necessarily mean it's not moly-fortified. Does anyone know if this is moly-free?
 
#6 · (Edited)
"Moly can cause excessive amount of “HEAT” if left in any bearings and it will destroy it in no time."

This is not a factual statement., and is based on a misunderstanding of a phenomenon that can occasionally occur in physically large roller bearings that are running unidirectionally under very light load and at high speed, or are subject to large rates of speed change. The moly reduces the friction so much that under the right conditions, the rollers "skid" instead of roll, and if the skidding is sustained, the rollers can develop flat spots that create noise and reduce bearing life.

The needle bearings in U-joints are NOT high-speed bearings. In fact, when there is zero angle between the driveshaft components connected by the U-joints, there is zero motion within the bearing. When there IS some driveshaft angle, the motion in the bearings is oscillating, not unidirectional rotation. It is difficult to maintain a hydrodynamic lubricant film in an oscillating bearing with grease alone, which is why the moly disulphide flakes in moly grease work so well in U-joints.

The moly forms a very thin film of solid extreme-pressure lubricant on everything that keeps the needles separated from the spider and the cups, and prevent metal-to-metal contact, wear, and eventual seizure.

Moly grease has been successfully used in U-joints for scores of years in automotive and heavy-equipment service, and as Valvoline stated on the tube of moly grease, is an ideal lubricant for U-joints.

From an authoritative technical source specializing in industrial lubrication:

"Greases containing moly are recommended for roller bearings subjected to very heavy loads and shock loading, especially in slow or oscillating motion such as found in universal joints and CV joints. If such greases are used in high-speed bearings, problems can be experienced with roller “skidding” where the bearing roller fails to rotate through the full 360 degrees due to reduced friction. As a result, the roller develops flat spots, and its service life is reduced."

As a real-world example, my 4WD Toyota 4Runner has had both front and rear driveshaft U-joints lubricated with moly grease since it was new. 17 years and 240,000 miles later, including lots of off-roading and towing, it is still running on the original U-joints, which show absolutely no evidence of wear or play. The U-joints are lubricated with moly grease at every oil change (~7.5K mile intervals).

The driveshaft and U-joint design in the 4Runner and FJ are essentially identical.

If the use of moly grease in U-joints resulted in "destruction in no time", I would have replaced MANY U-joints in those 17 years and 240,000 miles.

I think Toyota's recommendation to use lithium-soap chassis grease is probably based on eliminating customer complaints about sulfurous odor after lubrication, when a small amount of grease gets flung out of the U-joints and onto the adjacent hot exhaust system. This gets burned off after a few miles, but the odor can be quite noticeable for a little while.

I'd gladly put up with the odor for near-unlimited U-joint life. I use moly grease in the U-joints and slip joints of my '14 FJ because I intend to keep it running well past 300K miles.
 
#7 ·
"Moly can cause excessive amount of “HEAT” if left in any bearings and it will destroy it in no time."

This is not a factual statement., and is based on a misunderstanding of a phenomenon that can occasionally occur in physically large roller bearings that are running unidirectionally under very light load and at high speed, or are subject to large rates of speed change. The moly reduces the friction so much that under the right conditions, the rollers "skid" instead of roll, and if the skidding is sustained, the rollers can develop flat spots that create noise and can reduce bearing life.

The needle bearings in U-joints are NOT high-speed bearings. In fact, when there is zero angle between the driveshaft components connected by the U-joints, there is zero motion within the bearing. When there IS some driveshaft angle, the motion in the bearings is oscillating, not unidirectional rotation. It is difficult to maintain a hydrodynamic lubricant film in an oscillating bearing with grease alone, which is why the moly disulphide flakes in moly grease work so well in U-joints.

The moly forms a very thin film of solid extreme-pressure lubricant on everything that keeps the needles separated from the spider and the cups, and prevent metal-to-metal contact, wear, and eventual seizure.

Moly grease has been successfully used in U-joints for scores of years in automotive and heavy-equipment service, and as Valvoline stated on the tube of moly grease, is an ideal lubricant for U-joints.

From an authoritative technical source specializing in industrial lubrication:

"Greases containing moly are recommended for roller bearings subjected to very heavy loads and shock loading, especially in slow or oscillating motion such as found in universal joints and CV joints. If such greases are used in high-speed bearings, problems can be experienced with roller “skidding” where the bearing roller fails to rotate through the full 360 degrees due to reduced friction. As a result, the roller develops flat spots, and its service life is reduced."

As a real-world example, my 4WD Toyota 4Runner has had both front and rear driveshaft U-joints lubricated with moly grease since it was new. 17 years and 240,000 miles later, including lots of off-roading and towing, it is still running on the original U-joints, which show absolutely no evidence of wear or play. The U-joints are lubricated with moly grease at every oil change (~7.5K mile intervals).

The driveshaft and U-joint design in the 4Runner and FJ are essentially identical.

If the use of moly grease in U-joints resulted in "destruction in no time", I would have replaced MANY U-joints in those 17 years and 240,000 miles.

I think Toyota's recommendation to use lithium-soap chassis grease is probably based on eliminating customer complaints about sulphurous odor after lunbrication, when a small amount of grease gets flung out of the U-joints and onto the adjacent hot exhaust system. This gets burned off after a few miles, but the odor can be quite noticeable for a little while.

I'd gladly put up with the odor for near-unlimited U-joint life. I use moly grease in the U-joints and slip joints of my '14 FJ because I intend to keep it running well past 300K miles.


So I guess toyota engineers must be wrong.
My brother destroyed the u joints on his truck which was 1410 Spicer on his driveline front and rear.
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#8 · (Edited)
"My brother destroyed the u joints on his truck ...".

While there is no question that it is possible for someone to destroy the U-joints in their vehicle, can you provide ANY incontrovertible proof that the root cause of the failure was the use of moly grease as the lubricant?

I think not.

Different manufacturers may have different recommendations as to the optimum lube for their mechanical components.

The point I was trying to make is that the statement that the use of moly grease in U-joints would quickly lead to catastrophic bearing failure was incorrect, and that the failure mechanism that was stated (roller skidding) is not applicable to the oscillating motion in U-joints.

The fact that I have 240,000 miles on my original U-joints, lubricated exclusively with moly grease, was offered as proof that in Toyota truck driveshafts, moly grease provides exceptional U-joint service life AND resolves the stick-slip "clunk" in the slip joints.

It's likely that REGULAR relubrication to force out contamination and wear debris is more important than whether standard lithium chassis grease or moly-fortified lithium grease is used.
 
#9 ·
This is what I use in u joint Shell GADUS this has replaced Shell Albida EP-2
I work for the refinery and I get this stuff for free.
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He picked up the wrong grease gun which was loaded with EXON RONEX which ultimately destroyed his u joints on his truck. This stuff is like MUD.
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#10 · (Edited)
Not to get in a war of words, but unless a carefully controlled, long-duration experiment was conducted with two sets of new bearings, each lubricated exclusively with one type of grease, how can anyone possibly state with confidence that the use of a particular lubricant "caused" the bearing failure?

It sounds like your brother had a vehicle with many miles on it.

At some point he "accidentally" lubed the U-joints with a grease containing 3% moly.

We don't know the actual condition of the U-joint bearings at the time the moly grease was introduced because they had already been in service for some time (months? years?) and were not disassembled and microscopically examined at the time where they were lubed with the moly grease, correct?

At some point later in time (minutes? hours? days? months?) he had problems with the U-joint bearings.

But we have absolutely ZERO proof that the bearing failure was "caused" the moly grease, correct? The connection is only an assumption, without any specific evidence to back up the assumption, correct?

Any more than the bearing failure was "caused" by the brand of gasoline in the tank, or the phase of the moon? It's like saying "I installed premium Bosch wiper blades, and the very next day the TPMS battery died on my right-rear wheel. Bosch wiper blades will kill your TPMS batteries."

(As part pf my day job I perform failure analysis on complex electromechanical systems, and it's SOP that a very meticulous, detailed analysis of the parts themselves and all the other factors involved is necessary to develop the data that will lead to a definitive conclusion. Assumptions are not permitted.)
 
#11 ·
Sounds good. At time of this incident, his truck only had about 245K on the clock.

Long story short, the u joint on his truck got so hot that destroyed the rubber seals and ultimately destroyed the u joints as well.
But I have to say that we all have to live with the decision we make in life whether it is right or wrong.
Every man is for himself in this place or any other.

Unknowingly he failed to fallow proper procedure and recommendation from Dana-Spicer and he has to live with his decision.


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#14 ·
Very unlikely. If one u joint goes bad I may say that was bad luck. But when both explode at the same time, it is more than bad luck.

Lol, he doesn’t care about that since he can afford it. He picked up a 2018 Ford Raptor.

The other truck with the exploded u joint is still at his house. It is a Ford Roush and he is going to cut it up and make a Rock Crawler out of it
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#15 ·
If both joints failed at the same time that is evidence of something that caused both to fail, but the fact that others have used moly grease in their U joints and have not experienced failures with them does indicate that there is a possibility that something else could have caused your friend's failure.


Since it is a Roush F150, which is a heavily modified truck, one version was advertised as the world's fastest truck, probably that is an indication that there could have been something else to the story besides choice of grease.


Extreme U-joint angles which can be caused by lifting is one. High HP / torque through a driveshaft with non-factory angles, those things can put a lot more load into a U joint than was originally designed for.

N
 
#16 ·
The U joint is not a high speed bearing. It has needle bearings which essentially roll back and forth. Using a quality moly grease should be safe for U joints. I wouldnt worry about it. The driveshaft spins fast obviously, but the U joint is not spinning like a wheel bearing.

Just sayin
 
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#17 ·
Light moly wont cause a problem here, assuming a stock setup, so all is well.

The moly isnt needed, and i dont think you need moly in your slip yoke either, provided you use a grease that can perform appropriately.

I cant see how a moly grease would cause a sulphur smell, and highly doubt thats a reason why toyota specs non moly grease.

Many of the maintenence items and recomendations are based on extending the maintenence interval.
 
#18 · (Edited)
(Snip - and I know this is an "older" thread)

I cant see how a moly grease would cause a sulfur smell, and highly doubt thats a reason why toyota specs non moly grease.
Moly grease on a hot exhaust smells distinctly like sulfur because "moly" is molybdenum disulphide, MoS2. A compound of one atom of molybdenum bonded to two atoms of sulfur.
 
#19 ·
On CVs, the inners use different grease to the outers. Why? Range of movement.
Inner tripod joints have a range of movement similar to typical universal joints, while the outer CV has a much larger range of movement.
I would imagine that lifting the truck (increasing the range of movement each rotation) would have a greater effect on the Universal joints (and CVs in IFS) than choice of grease.
That is one of the reasons diff drop kits exist - they decrease the angles on the CVs, but increase the angles on the U joints.
 
#20 ·
I have to say, FJTest gets quite a bit of flak here on these boards for his direct approach, but I really appreciate the wealth of knowledge that folks like FJTest and yes, even manual-loving amaclach :), bring to the table. We are really fortunate to have these kinds of in depth technical discussions here that truly benefit us all. Thanks.
 
#23 ·
We cant say what lube is best, nobody knows till ProjectFarm tests it all? He probably has..lol
But I can say my 2005 OEM Tundra AC center OEM bearing just failed (rubber).
So Im putting all new spicer U-Joints & center back in while my shafts out thats for sure. Never changed any on it yet, Spicers are Brutes! The spicer center I ordered from RockAuto has Toyota molded into the rubber. Sure thats common knowledge here.
I'll run a Moly lube in them again just as I have every spring/fall since the truck was new. Im nearing 400k miles on it now so Moly must not hurt U-joints too bad. Its simply not the 👹 its made out to be.
True' U-joints have needle bearings but they aren't being used in a high speed friction application here. Thats were issues occur with Moly. Valvoline Moly lube specifically benefits U-Joints according to their tube I read last yr.
Ive mostly used Molly 3 or 5% now over 40yrs I know of.
These roller bearings do more slow rolling, rarely do complete rotations even so they benifit from the slicker Moly. Or is it slickyier, slikyiest? Huum' I must ponder this later?
Know what a mean Vern?
Crazy how all my U-joints are still perfectly tight, I dont even know how long my center bearings rubbers been bad, heII the rubber is gone. Bearing spins by hand, the shaft/bearing is not touching its frame/surround & I have no vibration whatsoever. Just noticed it when I greased my joints up for this winter.

Fwiw: My wifes 2007 4Runner still has all its original joints, all tight but it only has 155k. Always use Molly on it too.
My youngest son has my old 1991 Deluxe pickup, he just uses it weekly to haul his trash off now (lives in country). But the old Deluxe had over 250k miles back in 2003 when I gave it to him for college being good on gas. Just no telling how many miles are on it now but I always lubed it with Moly too.
I highly doubt he ever lubed it once & Ill lay money its not had one new U-joint yet. I say this because I aint heard "Dad' my trash trucks vibrating can you come fix it?" & me say'n well' :poop:!