3-Point Hitch Surging in up position

[Deere Dude]

I have a 3720 and I had replaced the big plastic pan underneath the seat and where all the controls go through such as the 3PT control and the FEL control and parking brake and all of those things to operate the tractor.

Since I did that I noticed after I got home with the tractor, wouldn't you know, that when the 3PT control lever is all the way in the up position, I noticed a surging sound or a deadheaded pump sound coming from a pump of some sort. If I lower it about 1/2" the noise goes away. When it is all the way up, the performance of the tractor decreases somewhat. Maybe 10-20%.

This happens when something is on the 3PT and even when nothing is on it.

I talked to the mechanic who worked on the pan swap and he said he never took that lever off, but just the knob and slipped the pan over the top to get it off.

It just seems to be a coincidence.

Does anyone have any ideas. I know I can put a hard stop in somehow so the control lever don't go all the way up, but I don't really want to do that just yet as long as there is a warranty on it yet.

Just a little info I can talk to the dealer about would help.

Thanks.

 

[beenthere]

Sounds like it is out of adjustment, and needs to be readjusted. Not sure why the mechanic wouldn't identify the problem right away, and not come up with the excuse "I didn't do anything".
Do you have the tech manual for your tractor?

 

[LD1]

It sounds like the feedback linkage is out of adjustment. If it is too tight (at least on my tractor) it will still be trying to lift even though it is physically out of travel.

If the "shop" had your tractor, and repaired something in that "area" and now all of the sudden this happens....I'd take it back and make them make it right.

 

[Deere Dude]

No, I don't have a manual, but LD1 may be on to something. I never heard of a feedback linkage, but it sure is doing something. I though at first and I questioned the mechanic, if the slot for the arm is exactly like the old one. I though maybe the pan was formed different with a higher slot and a higher stop. It seems to be the same location and size.

 

[beenthere]

LD1 is onto the problem.
Here is a pic of the feedback linkage on the 3720. It is on the left side between the fender and seat. Just a short rod that is adjustable and likely needs just a small tweek.
There is a procedure, but likely a small adjustment will let you know real quick if that is the fix to the problem. I am thinking lengthening that rod will tell the internal valve that the rockshaft is at its highest position and not try to raise it higher.

 

[Deere Dude]

LD1 is onto the problem.
Here is a pic of the feedback linkage on the 3720. It is on the left side between the fender and seat. Just a short rod that is adjustable and likely needs just a small tweek.
There is a procedure, but likely a small adjustment will let you know real quick if that is the fix to the problem. I am thinking lengthening that rod will tell the internal valve that the rockshaft is at its highest position and not try to raise it higher.

Thanks folks. That's what it was. It was easy to fix when I knew what to look for. Just that info paid for my subscription on TBN. :thumbsup:

 

[LD1]

Glad you got her fixed:thumbsup:

 

[JordanFTW]

I have the same problem on my newly acquired 4300, thanks for bringing this up. The fix (ROCKSHAFT POSITION FEEDBACK LINKAGE ADJUSTMENT) on the 4300 is outlined on page 679 (11-29) of the manual.

6. Using a tape measure, measure from the top of the
PTO shield to the center of the pin in end of
lift arm. Lift arm should raise to 350ｱ3 mm
(13.8ｱ0.12 in.) as shown, without engaging the
relief valve. Check that there is 25.4 mm (1 in.) of
slack above the vertical height.
7. If specification is not met, lengthen the lift arm
position feedback rod to increase, or shorten to
reduce the maximum height until within
specification. The relief valve should not engage.