DK35 se hst transmission problems, again

[hammer1954]

Bought a used DK with 350 hours on it several years ago. At around 600 hours it wouldn't move correctly. It was very slow to respond to pedal change and it would barely climb a 20% grade in low range. Dealer thought transmission had failed and proceeded to repair. I believe they replaced the transmission but I do recall them saying they had to split it a second time due to an issue with a pressure relief valve in the hydro system. They reassembled it and it worked perfectly again until about 1100 hours. I was going up the road to access my field, full throttle, high range, cruise on. When I reached the turn to my field, I tapped the brakes to disengage the cruise and turned into the field and came to a stop, slowed the engine to an idle, turned on the pto, stepped on the go pedal to proceed, now in middle gear, tractor wouldn't move. I checked to see if it was in gear, which it was. I put the go pedal all the way down to the floor, it would bare move, I had to increase the throttle to about 1200 to 1500 rpm before the tractor would move at all. Play for a while and decided to take tractor down to the house, I discovered when I let off the pedal the tractor didn't immediately start to slow an usual but instead just rolled to a stop, slowly. I went to the dealer and no one there recalls working on my tractor, no records were kept by the dealer. They picked up the tractor, tested the hydrostatic trans pressure and it was in spec. and they returned the tractor to me, and I still have to throttle up to at least 1600 rpm before tractor will move in middle range. Two major internal transmission issues within 1150 hours? What is happening? All I can recall is that the original person who worked it said the second time they split it the problem was a "relief valve" in the system which they replaced. Now 600 hours later I believe the same issue is back. The dealer now plans to do another pressure after I went at him again today. HELP, anyone have any ideas I haven't haven't had a working tractor/loader since September. I need a working tractor.

 

[Robin Veerman]

HST tractors need to be operated at a higher rpm than geared tractors in order to spin the HST pump fast enough to move the tractor as required. However is there any chance that one or both of the brakes are sticking? How many hours since fluid/filters were changed? LUK…

 

[hammer1954]

HST tractors need to be operated at a higher rpm than geared tractors in order to spin the HST pump fast enough to move the tractor as required. However is there any chance that one or both of the brakes are sticking? How many hours since fluid/filters were changed? LUK…

Before this recent event if you you were idling @ 800 rpm, warmed up, in mid range, if you stepped on forward pedal it would start to move then stall. Now it just keeps running, no attempt to move until rpms are ramped up to above 1600. The pedals also went soft also, no feedback, tractor keeps moving without speed decrease when you let off the go pedal, it just keeps rolling, no hydro holding back. I have operated this tractor extensive using the loader, bush hogging with a 6' bush hog on hills that would scare any sane person as my 30 acres are anyting but flat, I also run a 6' Blizzard snowblower. My tractor totally changed as far as the operation and feel of the hydro from the instant I came off cruise, it slowed rapidly as normal so I could turn as normal, I idled down to engage the pto and shift from high to mid range, stepped on the go pedal and nothing, it wouldn't attempt to move or stall as I expected. It has never been the same since. I have have used it for 800+ hours, I know that tractor like back of my hand, it changed immediately. I am extremely familiar with hydro tractors as I was raised on a farm and I have owned other hydro tractors in the past. Some thing is by-passing in the tranny.

 

[IndyIan]

Before this recent event if you you were idling @ 800 rpm, warmed up, in mid range, if you stepped on forward pedal it would start to move then stall. Now it just keeps running, no attempt to move until rpms are ramped up to above 1600. The pedals also went soft also, no feedback, tractor keeps moving without speed decrease when you let off the go pedal, it just keeps rolling, no hydro holding back. I have operated this tractor extensive using the loader, bush hogging with a 6' bush hog on hills that would scare any sane person as my 30 acres are anyting but flat, I also run a 6' Blizzard snowblower. My tractor totally changed as far as the operation and feel of the hydro from the instant I came off cruise, it slowed rapidly as normal so I could turn as normal, I idled down to engage the pto and shift from high to mid range, stepped on the go pedal and nothing, it wouldn't attempt to move or stall as I expected. It has never been the same since. I have have used it for 800+ hours, I know that tractor like back of my hand, it changed immediately. I am extremely familiar with hydro tractors as I was raised on a farm and I have owned other hydro tractors in the past. Some thing is by-passing in the tranny.

Sounds like its the same thing again, an issue with the pressure release valve. Must be getting partially stuck open? What's your hyd fluid look like? what type are you using? I wonder if its somehow gumming things up?
There's a free download of the daedong EX/ DKSE manual somewhere on here, its pretty detailed on how things work, have a look at that.

 

[JimR]

Before this recent event if you you were idling @ 800 rpm, warmed up, in mid range, if you stepped on forward pedal it would start to move then stall. Now it just keeps running, no attempt to move until rpms are ramped up to above 1600. The pedals also went soft also, no feedback, tractor keeps moving without speed decrease when you let off the go pedal, it just keeps rolling, no hydro holding back. I have operated this tractor extensive using the loader, bush hogging with a 6' bush hog on hills that would scare any sane person as my 30 acres are anyting but flat, I also run a 6' Blizzard snowblower. My tractor totally changed as far as the operation and feel of the hydro from the instant I came off cruise, it slowed rapidly as normal so I could turn as normal, I idled down to engage the pto and shift from high to mid range, stepped on the go pedal and nothing, it wouldn't attempt to move or stall as I expected. It has never been the same since. I have have used it for 800+ hours, I know that tractor like back of my hand, it changed immediately. I am extremely familiar with hydro tractors as I was raised on a farm and I have owned other hydro tractors in the past. Some thing is by-passing in the tranny.

When was the last time you changed the hydraulic filters and oil? Is your oil level where it should be?