Fluid in the front axle and a front tire pressure w/loader? L3940

[Grateful11]

We were checking all the fluids yesterday, took delivery this week and everything
looks fine except the front axle didn't show any oil when I backed out the check
level plug. I took the fill plug out and twisted up a clean blue shop towel stuck it in and
it appears to be 1/8 - 1/4" low. Now according to my manual you can run
UDT, Super UDT or SAE80-SAE90 gear oil in the front axle. Well maybe I'm
thinking wrong but in my mind there's a big difference in Hydraulic oil and
Gear oil? I want to pick up some but I have no way of knowing exactly
what's in there when the manual gives you 3 choices. I guess I may call the
dealer tomorrow and see what they put in there because if I'm not mistaken
they're shipped dry, as the front axle appeared to be partially disassembled
when I saw it in the crate.

Now for the tire pressures on our L3940. The tires are R4's the rears are filled
and the check off sheet says they set them to 19psi and the fronts to 45psi.
The manual says for 10-16.5 6PR use 20psi, the loader manual says the same
thing and doesn't mention anything about increasing the pressure in the front
for a loader. This is our first 4WD tractor so you'll have to excuse all the
questions, I did search the forum for tire pressure but didn't really find what
I wanted.
Thanks

 

[bp fick]

Having the front axle read low upon delivery is pandemic. The fact is that these front axles hold a lot of lube. The dealers sometimes fail to top off, and even if they do, if you use it an hour or two, the air gets worked out and they read low. Top it off. Check again in a week. This is widespread issue that isn't really an issue at all, just the nature of the beast.

You will get a lot of pro udt and sudt support here, but an equal amount of firm believers in gear lube. Myself? I'm not a zealot either way, but there's gear lube in mine. 75w-90 gear lube. Semi-synthetic. Sold almost everywhere. WalMart, TSC, Auto Parts Stores, you name it. Shoot, K-Mart likely has it. Standard GL-5 80w-90 is sold everywhere.

Air pressure. Just checked all four of mine today. I run 2 lbs lower than the sidewall recommended MAXIMUM. Good to remember that sidewall is the max, not the normal, imho. Work off of what's on the sidewall from the tire builder. You could safely go 4-6 lbs off that, if you want a softer ride.

 

[dex3361]

Most of the Kubota tractors come with SUDT in the front axle but the good thing is the UDT and SUDT are compatible. Pick up some UDT and top it off. When you change the front axle fluid out put the 80-90 gear oil back in. The front tires are good to fill to about 5 psi below the max tire (side wall stated) rated pressure with a loader. R4s are not as bad to roll a tire off the rim.

 

[RickB]

Remove one of the drain plugs and let enough oil out to figure what it is. Buy some and top off.

 

[Ken45101]

Air pressure. Just checked all four of mine today. I run 2 lbs lower than the sidewall recommended MAXIMUM. Good to remember that sidewall is the max, not the normal, imho. Work off of what's on the sidewall from the tire builder. You could safely go 4-6 lbs off that, if you want a softer ride.

At least on the bigger tractors (e.g. M5040) with R1 tires, their tire capacity is well below the loader capacity and really sag under load if not inflated to max. I've been afraid of breaking the bead loose when I have a full bucket.

It seems that the loaders are rated much higher than the rubber that has to support them

Ken

 

[RTII]

The service dept at my dealer told me the tractor was shipped with SUDT in the front axle but at the first service, if they were doing it, they would change to the 80-90 gear lube. Not only do they like the viscosity better but it's cheaper for the customer than the SUDT. So that was my course. I topped up with SUDT (the remainder will be used during the HST service) and I will change to the 80-90 1st service.

 

[Grateful11]

I called the dealer and asked for some in the service dept. and he said they
fill them with UDT and said the same thing that's been mentioned here that
after a few hours use they usually work the air and stuff out and the level
drops a bit. I really like the Service guys at the dealership where we bought
it but the one salesman we dealt lacks a lot to be desired, first you don't tell
a customer what they want if the customer has a pretty good idea of what
they want. We're planning on getting a backhoe and grapple when we can
and I mentioned getting a mechanical or hydraulic thumb for the BH and he
said, "what would you need that for?" I'm thinking to myself that's my business
and not yours. We have 85 acres here at the farm, 12 acres a 1/4 mile up the
road and rent another 10 acres so yes I can think of a lot things I could do
with a BH and a thumb. I guess I should have mentioned that he first recommended
that we rent a mini excavator instead of even considering a BH. My wife is
even thinking of a 72" belly mower but that's got to be some pretty big bucks.
She'd like to have it for clipping pastures instead of using a bush hog but
the Kubota belly mower looks difficult to install, I don't see a drive over
option or rotating castors.

I'm getting way Off Topic gotta stop.

 

[Grateful11]

I did check the sidewall on the fronts and sure enough it says 45psi max.
I may drop them by 5 psi and see it rides a bit better. I know what y'all mean
about front tires and heavy loads with loader our IH 574 has a Manure
bucket and when it's slam full it's a load and I've seen the sidewalls do
pretty serious flexing.

 

[Grateful11]

Well it took an entire quart in the front axle before I got anything out the
check hole. Seems the dealers need to drive them around the building and
let them set for a few minutes and check the level before sending them on
their way.

 

[bp fick]

Problem is it takes more than a drive around the building to work the air out.
Hopefully, the dealer or the manual reminded you to check the fluid levels, for exactly this reason. Good job. One quart out of 2-3 gallons isn't much.