JD 3X20 3PH Control

sunnyside360 · Oct 10, 2007

I bought a new JD 3720 Cab tractor in April of this year and have been using it mainly to mow approx 6 acres of grass all summer with a 72" MMM. Today I hooked up a 60" rotary cutter to the 3PH to do some field mowing. To my surprise I found the 3PH control to be extremely sensitive and the "stop" mechanism doesn't seem to be very reliable in lowering the rotary mower to the same height each time it is raised and lowered.
Just wondering if this is normal with the 3X20 Cab tractor or if there is something that needs adjusted, or etc.

Killer_B · Oct 10, 2007

Sunyside,

My 3320 3 PH control (AKA Rockshaft Controller) is quite smoth and reliable in returing to a specific position. Looking forward to other replies on the subject.

sunnyside360 · Oct 10, 2007

Killer_B said:
Sunyside,

My 3320 3 PH control (AKA Rockshaft Controller) is quite smoth and reliable in returing to a specific position. Looking forward to other replies on the subject.

I'm wondering if the 3 PH control is different between 3X20 cab tractors (like mine) and 3X20 non-cab tractors?? My control lever is very short and seems to be connected to a cable which runs down to transaxle housing.

radman1 · Oct 10, 2007

I agree, the cab version of the 3pt control is not the best. The control seems too tight/stiff. I need to try oil or grease on the friction areas. However, it seems to lower to the same position when I lower it to the stop. When you set the lowering stop, be sure to raise it up fully and then lower it all the way to the stop. Adjust the stop a little and repeat again. Once you find the right location for the stop, it should stay repeatable. If you only move it slightly and then change the stop, it does not seem repeatable.

KennedyDiesel · Oct 10, 2007

I wanted to upgrade to a cab tractor, but there's just no way I could deal with the rockshaft. I'd try an open station unit once to see how you like the feel.

jd110 · Oct 10, 2007

You are correct. The open station tractors have no cable in the operation. The lever is attached directly to the rockshaft valve. Be sure the cable is securely attached on both ends. It seems to me that I found one that the lever moved very stiff which caused erratic operation. I think there is a brake mechanism that can be adjusted for smoother operation .

jd110 · Oct 10, 2007

I have attached a picture of the linkage under the cab. The nut labeled "A" is the one to adjust the tension on the lever. Try loosening it just enough to permit smooth operation. If you go too far, the lever wont stay in the position you want.