B7800 low hydraulic/transmission fluid

jim_galloway · Dec 25, 2005

I just bought a new B7800 with FEL less than a week ago. This is my first tractor, so operating this great piece of equipment has been a fun learning experience. However, this morning when i went to use the tractor, I noticed some hesitation with the HST...like the transmission was just not engaging like it should. I decided I should investigate the obvious things and was shocked to discover that the transmission fluid wasn't even reaching the dipstick, and I could't see any fluid down the filling hole--basically dry. While looking over the tractor I also found a leak in the hydraulic system (when in use) at a port junctionfor the FEL hosing.

Is the Hydraulic fluid for the FEL the same fluid as in the transmission? In other words, could a leak up by the front-end loader cause the transmission fluid level to drop?

I haven't talked to the dealer yet, but will call him tomorrow. Just got this thing last Wednesday, so hopefully he will make it right, real quick. Should I be concerned about any possible damage or wear to the transmission due to running it with low fluid for a couple of hours?

Thanks for any advice. I have found this forum to be very useful.
Also, should I be concerned of doing

MadDog · Dec 25, 2005

I think it's the same fluid, running through two pumps; one for the power steering and one for the hydraulic system. Th
the B7800 takes a LOT of hydraulic fluid; close 5 gallons as I remember, so if you were losing it fast enough to compromise the transmission, you probably would have noticed a gusher from the leak. Should be OK, therefore, but insist that your dealer check it out and replace anything w/damage. Also, I'd have him check your transmission fluid strainer now, rather than waiting for 50 hrs and perhaps replace the hydraulic filter as well.

Hope this helps.

Skidmark25 · Dec 25, 2005

Jim,

I have a B7610 which is one click down from the B7800. All of the hydraulics and HST is from the same hyd. fluid.

Hope this helps and I'm sure your dealer will make it right.

aloha · Dec 28, 2005

On my B7800, when I first pull out the dipstick it is always dry all the way to the bottom. I then put it in and pull it out and it shows the level where it should be. My best guess is that the dipstick is in a tube that drains when the tractor runs, and has an airtight seal that prevents the fluid from rising up to the proper level until the seal is broken by pulling the dipstick out.

QueBota · Apr 26, 2007

aloha said:
On my B7800, when I first pull out the dipstick it is always dry all the way to the bottom. I then put it in and pull it out and it shows the level where it should be. My best guess is that the dipstick is in a tube that drains when the tractor runs, and has an airtight seal that prevents the fluid from rising up to the proper level until the seal is broken by pulling the dipstick out.

I have a 2910 and have noticed this quite a bit. If the tractor sits for a few days and I check the fluid before operation the stick will be dry. If I reinsert the stick and check again the fluid will be right at the full mark. Anyone else notice this? I pull the stick and lay it on a blue shop towel to check the fluid level, I have a hard time seeing the fluid on the yellow stick.

Thanks,
Dave

Fjord · Apr 26, 2007

dpdee13 said:
If the tractor sits for a few days and I check the fluid before operation the stick will be dry. If I reinsert the stick and check again the fluid will be right at the full mark. Anyone else notice this?
Dave

Yes , I have noticed that on my B7800 before and just always assumed that I hadn't looked hard enough the first time. If other people are noticing the same thing then I guess it's not my imagination, but I don't have any theories of my own as to why.

DieselPower · Apr 26, 2007

Not familiar with the dipstick on the tractor but this might be what is causing the "dry" dipstick on the first pull after setting. If it has a o-ring or rubber grommet on it, it may be pushing the stick up after some time. Next time try to push the stick in before pulling it and see if it goes in any. Just a thought.

chrisjbell · Apr 26, 2007

dpdee13 said:
I have a 2910 and have noticed this quite a bit. If the tractor sits for a few days and I check the fluid before operation the stick will be dry. If I reinsert the stick and check again the fluid will be right at the full mark. Anyone else notice this? I pull the stick and lay it on a blue shop towel to check the fluid level, I have a hard time seeing the fluid on the yellow stick.

Thanks,
Dave

I get the same thing with my B7300. I use the blue shop paper towel trick too, as that yellow plastic does *not* make it easy to see the fluid on it.

I should replace that thing with a metal dipstick. Hydro fluid isn't all that easy to see on one of them, either, but it is a lot better than the plastic...

Dascro · Apr 26, 2007

I have a B7610 and have the exact same situation with the dipstick. When i first pull it out it is doesn't show any fluid level. When I re-insert it and then remove it the hydraulic fluid is always at the full mark. I also have to use a blue shop towel to check the level as the yellow tube does not show hydraulic fluid easily.

Dave

mmcdermott1 · Apr 27, 2007

I think the kubota design is fairly common on all models. You more than likely have a hydrostat transmission that sucks oil from the transmission case. You also should have an external hydraulic pump that sucks out of there as well that fees the loader/3 point. If you leak anywhere in the system, it will drain the hydraulic oil source for all. You should have two strainers, one on the right and one on the left. If you follow these out, you should find that one goes to hydrostat and the other goes to the pump but both are fed from transmission.