JD 4600 HST sluggish when changing directions

[ChuckB72]

I have a 2000 4600 HST that is sluggish when changing directions from forward to reverse and visversa. I have had the tractor about 4 months and up until the last week or two it has worked fine. It does't seem to be as bad when it is cold. I took it to the dealer a week ago and they changed the fluid and filter and said they couldn't get it to act up. I drove it back to my shop about a quarter mile away, put a blade on it started blading and it seemed to be working normal. About 5 to 10 minutes later and several times of changing directions it started acting up again. When it happens and you chang directions, there is a lag of about 3 to 4 seconds before the tractor starts moving in the opposite direction. Any Ideas? Please

Chuck

 

[wthompson]

l haven't had any trouble with the HST drive on mine, but i would like to know what you figure out. Have you checked the linkage? Sorry i can't help. Anyone else have a suggestion?

 

[mfreund]

On the 4x10 series there is return springs that push the pedal back up. I wonder if the 4x00 series is the same. Could the linkage need a shot of lube?? I am fairly sure that it would not let you go in 2 directions at once.

 

[ChuckB72]

I have checked the linkage and it appears to be ok. The pedals move fine. It acts more like it a hydro problem. There is an electro-magnet along side the foward pedal that seems to have a nut broken off of it, letting it rub against the side of the pedal arm. I'm not sure what its function is.

 

[wthompson]

That electromagnet is the cruise control. There is a micro switch under there as well but i think thats for neutral start. Wish i could be more help.

 

[wthompson]

this is a diagram of what hst pedals should like. With tractor engine off, move each pedal and watch the movements of linkages to hydro.

 

[RoyJackson]

Aren't there poteniometers below the HST pedals?
Seems like I've read threads about this...they were concerning the 4300 or 4400, IIRC.

 

[ChuckB72]

Aren't there poteniometers below the HST pedals?
Seems like I've read threads about this...they were concerning the 4300 or 4400, IIRC.

This model doesn't have the poteniometers.

 

[ChuckB72]

That electromagnet is the cruise control. There is a micro switch under there as well but i think thats for neutral start. Wish i could be more help.

That makes sense. I should have thought of that myself.

 

[ChuckB72]

I did forget to mention that when the tractor does start moving that it will get up to speed where ever you have the pedal set. It just takes it a while to get there. And once you get up to speed and you start up a hill or put a load on, it doesn't seem to slip. When you let off the forward pedal sometimes it doesn't seem to slow down as fast as does when its working right.