Lesson Learned

[deminin]

I just finished rebuilding the front axle on my B2910HSD a few days ago. One of the Korean bearings on the Spiral Bevel Shaft (Pinion Gear) froze up and spun inside the axle housing...ruining it. The total parts cost was about 648 dollars, plus about $90 for a Kubota maintenance manual. I replaced the axle housing, the bevel shaft, and installed new bearings...it really wasn't too bad of a job....I had to buy a full set of spacers to get the ring and pinion gear clearance set correctly, but they were only about $20 for a full set. I figure I saved about half of what the dealer would have charged to do this.


I had been using Super UDT in the front axle...per the owners manual...but, never again. A gear housing should have 80/90W gear oil...IMO. Kubota does say to use either. I now have the front axle filled with Shell Rotella 80/90W, and will use only that heavier gear oil from now on....hydraulic fluid is simply to thin to give these gears and bearings the protection they need.

I would certainly recommend to anyone with a 4WD tractor to change over to the heavier oil during your next mantenance.

 

[simonmeridew]

Deminin:
Where do you live, that is, how cold does it get in the winter? We easily see -25 here in northern Vermont in January. I wonder if the 80/90 stuff will still lubricate at that temperature.
simonmeridew

 

[art]

Could have been several things to have caused that to have happened. It wasn't the oil! It could have been a lack of it, a bad bearing to start with, over load on the front end of it and the list goes on.

Don't get me wrong I from time recommend gear oil if there is a leak!

 

[deminin]

I'm in Central Missouri. I sometimes gets down to single digits in the Winter, but only for a few days. Luckily, being retired, I don't worry too much about the weather...if the forecast is for cold and nasty, we get some extra groceries, and I make sure I have plenty of gas for the generator in case we lose power, and we just ride it out.

I don't put too many hours on the tractor in the Winter, it mostly stays in my workshop. However, if I do decide to use it, I usually fire up my kerosene torpedo heater and aim it at the tractor for about 15 to 30 minutes before I fire the engine up. That way, the engine oil, etc., reaches 50 or 60 degrees before I hit the key. I really wouldn't worry too much about 80/90W oil even in cold weather....cars and trucks have been using it in their differentials for decades without adverse effects...in all kinds of weather.

 

[deminin]

Yeah, it's hard to say what triggered this failure. Lack of oil was not the problem...I check the fluids religiously in all my vehicles. If I had to point the finger, it would be the front bevel shaft bearing just went bad. All the bearings in the front end had Korea stamped on them....apparently, the Japanese outsource, too. I thought long and hard about trying to find a set of Timken bearings to fit this thing before I put it back together, but being over 100 miles from the nearest city where I might find some, I decided to go with the factory parts.

Looking at the tolerances called for in the Ring and Pinion, and the differential gears, I really think the heavier oil is good insurance. As you say, the heavier oil is also a plus if there are any oil leaks. This entire front axle asm. is put together with a series of O-rings to contain the oil...plus one oil seal at the rear of the front case where the bevel shaft connects to the drive shaft. Cleanliness and careful fitting of the parts....plus a little STP on the O-rings is definitely called for when putting this rig back together. That's one of the reasons why I decided to fix this myself....the odds of finding a mechanic who would take the time to do this job right are about 50/50. I learned a long time ago that If I want something done right, I probably need to do it myself.