front axle lubricant question

[bellweather]

I'm changing the front axle lubricant on my BX22 for the first time. According to Kubota I can use either UDT (Super UDT2) or 80w-90 gear oil. My question is, what's in the axle from the factory?

 

[thavil]

Your BX22 would have been filled with UDT or SUDT from factory.

 

[Danner]

Go with the gear oil. It's better at high pressure lubrication, and thicker, so there is less likelihood of leaking down the road.

 

[bx2670]

I put Lucas 75-90w in mine at 50hr and still have about a 1/4 of the 5th qt left to put in and I have 97 hrs on it now.I pull out the axle dipstick after each use to release pressure , it is slowly going down but it looks like new.

 

[namesray]

had a front axel leak on my b7800 at around 1000hrs. changed all fluids by the book. asked dealer about switching from the sudt in the front axel to the 80-90 gear oil. dealer said stick with the sudt as it is used in the hst pump and trans gears where there is high pressure just like the front axel. it would be the same as the gear oil but would be easier to just buy bulk sudt and keep all the oils the same and not have to worry about making sure i have 80-90 gear oil for the front axel. dealer said that he had 80-90 gear oil if i wanted it, but so far i have stuck with the sudt2 oil up front. for some reason danner's post above makes sence to me though. dealers advice makes sence too. i will ask dealer again. just posting my experiences so far.

 

[MHarryE]

SUDT is used to keep common fluids. Many gear oils are not compatible with brass in the hydro portion - EP or Extra Pressure additives. This isn't a problem in the front axle - no brass. Kubota must feel the SUDT provides enough lubricious for the front so they go with a common fluid across the board, but to a gear guy the EP additives in these bevel gear sets makes sense. I changed my L3710 to a synthetic 75W-90 at first change. I haven't changed fluid on my L5740 yet but plan to use a synthetic gear lube. It should provide extra protection and since Kubota lists it as acceptable in the manual, it appears there are no materials the EP additives will harm.

 

[johnk]

I had straight UDT in my front axle and changed to 80-90 gear oil when the change was due. You have to use the udt if you are under warranty though..

 

[Jay4200]

I changed to 80W90 in the front axle of my L4200 after one of my bezel seals started leaking at ~2100 hours. After about another 500 hours, the leak got worse, so I've bumped up to 90W140 in the front axle. I have to pour another pint in every month or two. I'll fix it someday...maybe to celebrate after I get to 3000 hours .

JayC

 

[bellweather]

Thanks for the replies. I have no leak issues, touch wood, so I'll stick with the SUDT for now since it's what I have on the shelf.

 

[JOHNTHOMAS]

Go with the gear oil. It's better at high pressure lubrication, and thicker, so there is less likelihood of leaking down the road.

I put Lucas 75-90w in mine at 50hr and still have about a 1/4 of the 5th qt left to put in and I have 97 hrs on it now.I pull out the axle dipstick after each use to release pressure , it is slowly going down but it looks like new.

What kind of high pressure would you have in a front axle and where would it be coming from?

 

[Jay4200]

What kind of high pressure would you have in a front axle and where would it be coming from?

Gears squashing together at a zillion PSI.

JayC

 

[JOHNTHOMAS]

Gears squashing together at a zillion PSI.

JayC

Would that be PSI or RPM? Would they be exerting pressure on the fluid system or pressure against each other? Are the gears actually pushing against each other or just engaging gear to turn gear? How fast (RPMs) would those gears be turning if the tractor is moving at 5mph or even 10 mph? I guess I have a lot of questions for the front geared drive experts that get so determined that one lubricating fluid in the front gears is so much better than another one. Isn't it true that the front gears are precision cut to turn each other in a submersed bath of lubricant that has no pump or filter or pressure trying to destroy the lubricant? Enquiring minds want to know. Who has taken the front gears all apart and looked at what's there??? Who's making it up as they go or just think they know how it works?:

 

[Ken]

Would that be PSI or RPM? Would they be exerting pressure on the fluid system or pressure against each other? Are the gears actually pushing against each other or just engaging gear to turn gear? How fast (RPMs) would those gears be turning if the tractor is moving at 5mph or even 10 mph? I guess I have a lot of questions for the front geared drive experts that get so determined that one lubricating fluid in the front gears is so much better than another one. Isn't it true that the front gears are precision cut to turn each other in a submersed bath of lubricant that has no pump or filter or pressure trying to destroy the lubricant? Enquiring minds want to know. Who has taken the front gears all apart and looked at what's there??? Who's making it up as they go or just think they know how it works?:

John I have taken the front apart on a L3600 and there is not much diffferance in design on other styles.
My reason for the disassembly was building a 180 foot barn and the operator left it in 4 whl drive on concrete hauling material into the barn . right side bearing gave away. as well as the pinion shaft gears and the housing attachment to frame. So the housing is not repairable needed new housing.
the gears look like stamped by a cookie cutter.and designed so any any metal floating or migrating to lowest level needs to go past the bearings. when ordering parts be sure to refill the checkbook 1st.

now as to the weight of oil book states use either.the rubber bands for seals thicker oil less likely to leak.
there is a metal cap at bottom of axle hubs carefully remove and look for metal grindings if so remember they went threw the bearings
Did this help the enquiring mind in making a decision . And not making this up. And know what I know.
ken

 

[Danner]

What kind of high pressure would you have in a front axle and where would it be coming from?

Torque being transferred from gear surface to gear surface. The local pressures on the lubricant are very high. Failure here wears the gears.

 

[ovrszd]

When I change I use 80-90w. I say Kubota uses UDT at the factory for simplicity. I also say they recommend either because they know 80-90w will work just as well and is warranty covered. But if they can suck you into buying their overpriced UDT, cha-ching for them.

 

[Bluegill2]

I'll be changing the L3800 to 80W-90 soon.

Yes, I've had the front-end apart on our old L3750. Very expensive rebuild!

 

[JOHNTHOMAS]

Thanks for the experienced replies. Are the gears/bearings immersed in lubricant or is it being squirted across the gears/bearings with some getting on them?

 

[ovrszd]

Thanks for the experienced replies. Are the gears/bearings immersed in lubricant or is it being squirted across the gears/bearings with some getting on them?

Same principle as your car/truck drive axle, splash system where oil is carried by the gears up into the case and then channeled by casing moldings to the bearing areas.

 

[Jeff F.]

I still do not understand where the oil pressure is coming from or why you would need to relieve pressure on the front drive by opening a cap. Is it the air pressure? I thought it is an oil bath system. I understand the pressure of the friction of metal on metal in the gears, but I do not understand how that would build up in the sealed front end. :confused3:

 

[sw03]

I still do not understand where the oil pressure is coming from or why you would need to relieve pressure on the front drive by opening a cap. Is it the air pressure? I thought it is an oil bath system. I understand the pressure of the friction of metal on metal in the gears, but I do not understand how that would build up in the sealed front end. :confused3:

called heat from amb temps or friction or both