Front axle lube looks funny

   / Front axle lube looks funny #1  

kolmstead

Member
Joined
Oct 9, 2007
Messages
30
Location
Ridgecrest, CA
Tractor
Kubota L2950DT and L39 TLB
I drained the front axle of my L39 a week or so ago and replaced the lube with Amsoil ATH, which is the synthetic equivalent of Kubota UDT. The 50 hour old lubricant appeared to have lots of small particles in it; I could see swirl patterns in the draining fluid. Looked like tiny flakes of brass, but the yellow color could have been from the oil. I didn't try rubbing the lube between my fingers to see if the particles were solid. Should have done that. I thought perhaps it was a special Kubota extra pressure additive.

OK, this past Monday I drained the 90-wt. gear oil from my L2950 DT front axle. It has 700 hours on it; 500 since I last changed the lubricant. It looked exactly like the L39 lube; swirls of tiny brass-colored particles. I know that the lubricant was absolutely clear when I added it, about ten years ago. The transmission lube on both tractors comes out clear, but it is filtered. Front axle fluid is not. If I had thought of it ahead of time, I would have glued a powerful magnet to each front axle drain plug while I had 'em out. Too late now. Wouldn't remove brass or aluminum (or water or air) particles, though.

Has anyone else observed this phenomenon? I suppose the contaminant could be air bubbles; I always drive tractors around right before I change fluids. At this point, I'm not too concerned. If the L39's lube had been contaminated and the L2950's was clear, I'd be upset. But I've owned the L2950 for twelve years, and its performance has been flawless.
 
   / Front axle lube looks funny #2  
It's just the way the fluid looks after use.
 
   / Front axle lube looks funny #3  
For me, I still would like to know why Kubota puts S UDT in the front diff? I am removing mine in my BX24 and putting in Amsoil Severe Gear 75W-90. It is a gear and should use gear fluid; but, that is me.
 
   / Front axle lube looks funny
  • Thread Starter
#4  
The L39 manual states that UDT or SUDT or 80W90 gear lube is good in the front axle. So I used Amsoil ATH, which is equivalent to UDT. The L2950 manual says to use 80W90, so that's what I put back in it. I was tempted to use ATH, but I have the old style seals on top of the bevel gear housings, and I was afraid that a thinner lube would start leaking out. At 700 hours, I'm probably nearing the end of the original seal life. Actually, one got replaced years ago after I poked a twig through it. At the moment, both are nice and dry, and I'd like to keep it that way.

I was surprised at the number of small leaks under the L39 with only 52 hours on it. Not drippy leaks, but greasy/dusty areas under the transmission and on both ends of front axle.

Drained all my waste oil cans yesterday (20 gallons!), so I can change the lube in the L2950 transmission this weekend. That should about wrap up the maintenance for this summer. I was impressed by how much dirt the optional particle separator keeps out of the L39's air filter. I need one of those on the L2950 also!

-Karl
 
   / Front axle lube looks funny #5  
Why do you keep using a hyd fluid in a gear fluid app?
 
   / Front axle lube looks funny
  • Thread Starter
#6  
Not quite sure which application you're referring to, Frank. I'm using ATH in the transmissions of both tractors, but the transmissions act as the fluid reservoir for the hydraulics also. The loaders and the 3-pt. hitches on both tractors and the backhoe on the L39 are all fed from the transmission fluid. I put gear lube back in the L2950 front axle as the owner's manual recommends. On the L39, the manual clearly states that UDT/SUDT or 80W90 gear lube is fine for the front axle. From its smell, I'm sure that ATH (or UDT/SUDT) has quite a bit of EP (extreme pressure) additive, which ought to work just fine in the front axle.

Changed the transmission lube on the L2950 today, so I'm about done with major fluid changes on the Kubotas. Seven more gallons of waste oil to haul to work...

-Karl
 
   / Front axle lube looks funny #7  
frank_miller said:
For me, I still would like to know why Kubota puts S UDT in the front diff? I am removing mine in my BX24 and putting in Amsoil Severe Gear 75W-90. It is a gear and should use gear fluid; but, that is me.

Are you aware that 'UTF' style fluids ARE INDEED rated for gear, tranny, diffy, and final drives.. as well as hyd and power steering applications???

My large fords use 10-13gallons of UTF in tehir common sump diffy/trans/hyds systems... my ex-4wd NH compact use dit in the front axle as well.

None of them have blown up setting in the barn due to using the utf in them, as specified by the manufacturer.. which is the entity that really should know what their machines take.

Just blindly using gear oil in an application that has historacly used gear oil, but does not have to due to different lube technologies now is like treating syphylis with mercury tincture because that's how they did it 'back in the old days'.. instead of using modern stuf like AB's now...

soundguy
 
   / Front axle lube looks funny #8  
kolmstead said:
I drained the front axle of my L39 a week or so ago and replaced the lube with Amsoil ATH, which is the synthetic equivalent of Kubota UDT. The 50 hour old lubricant appeared to have lots of small particles in it; I could see swirl patterns in the draining fluid. Looked like tiny flakes of brass, but the yellow color could have been from the oil. I didn't try rubbing the lube between my fingers to see if the particles were solid. Should have done that. I thought perhaps it was a special Kubota extra pressure additive.
Could be youre using lubes not compatible with yellow metal bearings? I understand that is slightly destructive. - more wear of the yellows over a long period.
larry
 
   / Front axle lube looks funny
  • Thread Starter
#9  
I doubt that there are brass/bronze bushings in the front axle of either tractor. But if there were, then GL-1 should still be okay. GL-5 can cause problems with copper-containing bearings.

I'm reasonably sure that what I observed was tiny air bubbles, seen through the amber lubricant.

Regarding Frank's concerns, I agree to some extent. But if Kubota says right in the owner's manual that UDT/SUDT is okay, then I'm not going to argue. The transmission and rear end are packed full of gears, and they last almost forever running in UDT/SUDT.

-Karl
 
   / Front axle lube looks funny #10  
kolmstead said:
I drained the front axle of my L39 a week or so ago and replaced the lube with Amsoil ATH, which is the synthetic equivalent of Kubota UDT. The 50 hour old lubricant appeared to have lots of small particles in it; I could see swirl patterns in the draining fluid. Looked like tiny flakes of brass, but the yellow color could have been from the oil. I didn't try rubbing the lube between my fingers to see if the particles were solid. Should have done that. I thought perhaps it was a special Kubota extra pressure additive.

OK, this past Monday I drained the 90-wt. gear oil from my L2950 DT front axle. It has 700 hours on it; 500 since I last changed the lubricant. It looked exactly like the L39 lube; swirls of tiny brass-colored particles. I know that the lubricant was absolutely clear when I added it, about ten years ago. The transmission lube on both tractors comes out clear, but it is filtered. Front axle fluid is not. If I had thought of it ahead of time, I would have glued a powerful magnet to each front axle drain plug while I had 'em out. Too late now. Wouldn't remove brass or aluminum (or water or air) particles, though.

Has anyone else observed this phenomenon? I suppose the contaminant could be air bubbles; I always drive tractors around right before I change fluids. At this point, I'm not too concerned. If the L39's lube had been contaminated and the L2950's was clear, I'd be upset. But I've owned the L2950 for twelve years, and its performance has been flawless.


The yellow particles could be a yellow paste that is used to check gear tooth mesh (?).

jb
 
 
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