Kubota BX1880, BX2380, BX2680 Transmission Fluid Change

BX1880 / BX2380 / BX2680 Owner Service Guide

The transmission case is the oil reservoir for the HST, the hydraulic lift, the power steering and the rear axle. Kubota calls for changing the transmission fluid and cleaning the transmission strainer every 400 hours. The strainer is a mesh screen on the end of the suction line that keeps filings out of the pump. The HST oil filter is due at the same time, so replace it while the case is drained.

Use only Kubota Super UDT-2. Standard tractor hydraulic fluid is not a substitute in the HST. A 5-gallon pail covers a full change with some left over for top-ups.

For a look at what this fluid is protecting, see our video:

Draining the fluid

1. Park on firm, level ground. Lower the 3-point hitch fully so fluid in the lift cylinder returns to the case.
2. Place the drain pan under the transmission case drain plug at the bottom of the case.
3. Remove the drain plug and let the fluid drain completely.
4. Clean the drain plug and reinstall it.

Cleaning the transmission strainer

Clean the strainer while the case is empty. It is mounted low on the transmission case and held in by a filter plate and one bolt.

1. Remove the bolt and the filter plate.
2. Pull the strainer straight out of the case. A little fluid will run out of the bore.
3. Rinse the strainer in nonflammable solvent until all filings and sludge are gone. Blow it dry from the inside out with low-pressure air.
4. Check the mesh for tears and the O-ring for cuts or flattening. Replace either if damaged.
5. Push the strainer back into the bore carefully so the mesh and O-ring are not damaged. Install the filter plate and bolt.

Replacing the HST oil filter

Replace the HST oil filter now, before refilling. The full procedure is on the HST oil filter page.

Filling and checking the level

1. Fill with new Super UDT-2 through the oil inlet at the rear of the tractor until the level reaches the upper notch on the dipstick. Start with about 2.5 gallons and add the rest a little at a time.
2. Start the engine and run it at medium speed for a few minutes. Do not drive the tractor or operate the hydraulics yet. Running the engine first fills the HST, filter and lines without starving the pump.
3. Raise and lower the 3-point hitch a few times and turn the steering lock to lock.
4. Lower the hitch, stop the engine and recheck the level with the dipstick. Add fluid to bring it to the upper notch.
5. Check the drain plug, strainer plate and HST filter for leaks.
6. Take the used fluid and filter to a recycling center or a shop that accepts used oil.

For when and how to check the level between changes, see our video:

Parts

Parts catalogs: BX1880, BX2380, BX2680.

Related

• HST oil filter replacement
• Front axle case oil change
• Hose and line inspection
• BX Owner Service Guide

To have the service done at Messick's, schedule service.