Too hot??

PaulB · Jun 25, 2000

Ran the rotary mower for 3 hours today nonstop, 80 degree weather. When I got done the engine temperature guage had not risen any higher than normal, but when I took off the pto I noticed that the U joint on the pto shaft was hot - not so hot you couldn't touch it, but hotter than warm. I then felt the pto spline on the tractor, and it was hot too, as were the rear drive housing, the brake boxes, and the hydraulic hoses. My conclusion was that my Super UDT was quite warm, bordering on downright hot. I was running at pto rpm, in high range, and at no time felt the tractor to be overworked. I do not use my brakes for steering, and I checked and the brakes do not seem to be rubbing. Normal?? or Problem??

Bird · Jun 25, 2000

After a couple of hours of mowing in 90 degree weather, the PTO spline on my tractor felt pretty hot today, too, when I disconnected it and put the tiller back on./w3tcompact/icons/wink.gif And I've noticed it felt just as hot when I was working in cooler weather, too, so I'm assuming it's normal.

Bird

MChalkley · Jun 25, 2000

PaulB - I've never seen one that didn't get warm. It's also quite normal for the hydraulic oil to get very warm. It's perfectly normal for the temperature to hit 140 degrees or so coming out of the HST. That would be pretty warm to the touch...

Mark

W5FL · Jun 25, 2000

The hydraulic fluid gets above 120 degrees even on a gear tractor - and that is pretty warm. I say 140 is HOT. That is the temperature of hot water when the temperature is turned to hot. Will scald you. The reason the fluid gets this hot on a gear tractor is simply the resistance in the hydraulic lines, hoses, and fittings with the pump up front and the oil being circulated, the temperature climbs pretty fast. Guess the engine warming up helps it a little too.

MChalkley · Jul 2, 2000

Wen - I agree that 140 is hot to the touch, but you have to remember that the fluid in automatic transmissions that are worked hard generally range from 175 on up. Depending on which study you look at, the life of petroleum varies from 100k to 240k at 175, but they all agree that the life expectancy decreases by half for each 20 degree increase in temperature. The main reason for this is that the viscosity of petroleum transmission fluid (which handles high temps as well as any commonly used petroleum oil, including hydraulic oil) starts breaking down at 220 or a little sooner. When I get the temperature sensor installed on my tractor, I'm going to be getting some interesting data, which I'll pass on. The only problem is, I've found out from experience with others who've had overheating problems with automatic transmissions using petroleum that the problems went away when they switched to synthetic because the temps went way down. So I expect my temps to be lower than typical. I wish I'd gotten the gauge in before I switched to synthetic. I know my temps went down over 20 degrees in a fairly controlled test I did, but I don't have the benefit of long-term gauge-watching to get the real nitty-gritty.

Mark

W5FL · Jul 2, 2000

140 degrees is cool to the fluid, but very HOT to the touch. Some how I am not properly calibrated for automobile temperatures with 195 degree thermostats. Everything is HOT.

Fortunately gears going around don't make much heat, so the gear tractors will run cooler.

Got all kinds of answers on the Super UDT, but am going to use it for the hydraulic fluid change this week end. I will use your freezer test to determine which fluid actually came in the tractor. Even the dealer does not know the answer to this one.