CK30HST surges in reverse

Retired guy · Mar 2, 2014

I have a 2012 CK30HST that surges in reverse especially in low range. Forward is fine at any speed any gear. This occurs mostly at low/creep speeds like running the rear PTO snow blower. There is 300 hours on the tractor. Is this an adjustment problem like the linkage or a major problem?

rmorey · Mar 2, 2014

When you say "surges", do you mean the RPM fluctuates? So, are you maybe overloading the pto with a blower full of snow? If that's the case, the engine rpm will bog down and resume when the load is removed. (assume HST) Does it do it without a load?

MotorSeven · Mar 2, 2014

Lube all the hst linkage with a dry lube...something like this that is not temp sensitive:

The Dry Lube

Work it in while it is still wet and see if that does not help. I do agree with rmorey, if it surges when blowing snow, try it with zero load on it and see what happens.

94BULLITT · Mar 2, 2014

My Bobcat would surge in forward or reverse at a light hydro pedal. It would as surge sitting still especially on a hillside.

Is everything else working properly on the hydro? Is everything adjusted properly?

Retired guy · Mar 3, 2014

I am talking about the hydrostatic-not the hitch. At very low speeds it is "jerky" in reverse even with the
blower in use. Press the pedal further to increase the speed and it disappears.

CJONE · Mar 3, 2014

Retired guy said:
I am talking about the hydrostatic-not the hitch. At very low speeds it is "jerky" in reverse even with the
blower in use. Press the pedal further to increase the speed and it disappears.

Contact MIE. I believe there is a neutral valve that can be replaced without splitting the tractor, I don't have my manual here so I am guessing on what they call it but I know the DK has one. Are you linkages in adjustment? This is on a 40-50DK But Bob will know if you have the valve on the 30. CJ

94BULLITT · Mar 3, 2014

CJONE said:
Contact MIE. I believe there is a neutral valve that can be replaced without splitting the tractor, I don't have my manual here so I am guessing on what they call it but I know the DK has one. Are you linkages in adjustment? This is on a 40-50DK But Bob will know if you have the valve on the 30. CJ

There are neutral valves under the floor mat on the right side.

CJONE · Mar 4, 2014

94BULLITT said:
There are neutral valves under the floor mat on the right side.

Thank you!! I was almost 100% sure. CJ

SSdoxie · Mar 6, 2014

There 2 neutral valves under the floor mat but 1 is on the right side other is on the left. Just below those neutral valves on each side are the high/max pressure reliefs.
It could be that the reverse neutral valve is pulsing on and off, working right at the pressure threshold of the HST pump. Mentioned that this surge is more noticeable in low than in medium. Working pressure on the HST is lower in low than in medium when trying to travel at same ground speed.
Swap the neutral valves from side to side and see if problem changes to forward, it so valve is sticking or not set correctly.