TRANS. SLIPPING?

[kbm3]

Hi guys, just got my used 1520 NH, and in learning how to work the controls etc., I inadvertantly was using the (med.) setting on the drive setting while pushing some heavy brush piles on my land. Now I know I should have been in Low range, but is it normal for the wheels to stop turning and the motor to seem to not drop rpms ie. the trans seemed to slip? I did not allow this to go on but for a few seconds, as at first I thought I was spinning.......but upon looking down at the wheels, I realised they were not spinning! Is this normal? I will not ever put the tractor in this position again (at least not intentionally) as this happened because I was learning how to operate. Keep in mind that traction was very good as I was on frozen choppy soil. It did not do it at all in low range......I have never had a hydro tractor so I am not sure if this is normal or not? If it is not, I want to get it back to the dealer, as I have only had it a couple of days! Thanks

 

[jinman]

That is completely normal for a hydrostatic transmission. On a gear tractor, you stall the engine if you are in too high a gear. On a hydrostatic, you stall the transmission. A relief valve lifts and all the fluid is returned to the reservoir. If you run it too long while it is stalled, the fluid will get hot, but not from just normal use. Most likely you will have to select the lowest hydro range to actually spin the tires.

It will take a while, but you will get used to this. Some people with good hearing can actually hear the relief valve open. Remember, on a hydro you are changing the gear ratio when you step down on the pedal. The most power to the wheels is in the lowest range with just slight movement of the pedal. You have to fight the urge to press the pedal down too far. It's not a gas pedal like on a car. All of us hydro owners have to go through this learning process. /forums/images/graemlins/cool.gif

 

[JimR]

As Jinman mentioned, You will get use to it. Don't worry too much about using the higher gears. There is the relief vavle to take care of high pressures. Enjoy your machine and work it like it is made to be used. You will find out what it can and cannot do in the different speeds.

 

[kbm3]

THANKS GUYS!!! I am very relieved to hear this is normal, and I knew I would get the staight facts from this group! Proud to be a member, and happy I didn't buy a lemon! Kerry

 

[djradz]

Jim/anyone, is there a scenario where you're at lower engine RPMs, so maybe you're not developing full pressure, and yet the transmission "slips"/ pump volume decreases, etc? ... or is the only situation where the relief valve goes? It seems like I had a case or two where I was running at something like 1800 rpms, pulling about a ton-and-a-half of firewood up a hill, in high/turtle and when I felt as if the tractor was about to stop, (I resisted the impulse to push on the pedal) and simply moved the throttle to something more like 2500 rpms, and kept right on going. Does this make sense?

 

[jinman]

</font><font color="blue" class="small">( It seems like I had a case or two where I was running at something like 1800 rpms, pulling about a ton-and-a-half of firewood up a hill, in high/turtle and when I felt as if the tractor was about to stop, (I resisted the impulse to push on the pedal) and simply moved the throttle to something more like 2500 rpms, and kept right on going. Does this make sense? )</font>

Duane, I stall my tractor a lot even in low range/rabbit. It's rare indeed that I can climb one of my hills (short but steep) in high/turtle with just the weight of the tractor with the FEL and a boxblade attached. I don't know if it's the relief valve or the hydrostatic just stalling, but once I stall, changing the rpm doesn't do anything for me. I'm sure there is a true stall in the transmission without the relief valve lifting, but it will take someone with a lot more intimate knowledge of the transmissions internal mechanics than me to describe how that would happen. /forums/images/graemlins/blush.gif

I just keep shifting downward until the tires spin (low/turtle). At that point I give up and take a smaller bite. Lately, it seems I get to that point a lot. /forums/images/graemlins/frown.gif