3-Pt Shudder

[Rockin' G Ranch]

I have a IH 384 tractor. Lately, I've noticed that when carrying a heavy implement while traveling, my 3-pt system shudders (load drops about 2"-3" then the hydrauics quickly corrects and picks the load back to original height). It happens about every 10 seconds and violently shakes the tractor. I checked my fluid and it is full. Any ideas what could be causing this?

[RonMar]

Does it happen with bouncing the impliment? It could be that the increased cylinder pressure when the impliment pulls some "G"s is causing the hydraulics to overpressurize and the relief opens and vents fluid to protect the structure. If you have a draft control, it then adds fluid from the pump to reposition the 3PH after it drops from the lost fluid. If it dosn't do it while stationary, that would be my guess. If it hasn't done it in the past with this same impliment and under the EXACT same travel conditions, It could be that the safety relief adjustment has shifted, or something is causing it to relieve at a lower pressure.

What is the rated lift force on the 3PH? What is the weight of the impliment?

[HarryVanderpool]

Does your tractor have draft control?
If so, I've seen heavy implments mess up it's head.
Fiddle with that and see what happens.

[jinman]

Originally Posted by Rockin' G Ranch

I have a IH 384 tractor. Lately, I've noticed that when carrying a heavy implement while traveling, my 3-pt system shudders (load drops about 2"-3" then the hydrauics quickly corrects and picks the load back to original height). It happens about every 10 seconds and violently shakes the tractor. I checked my fluid and it is full. Any ideas what could be causing this?

It sounds to me like your hydraulics are "hiccupping." That's when there is a leak in a position control system that lets the position change until it is sensed. Then a shuttle valve shifts and the hydraulics correct the position. The tractor is shaking as a function of rapidly moving that heavy implement. Normally hiccupping is a symptom of a leak in a check valve or the main lift cylinder has a worn seal that is slowly leaking. Some tractors have an inspection port where you can shine in a flashlight and watch what is going on, but most likely you will have to pull the hydralics and rockshaft out to repair and correct the problem.

Many tractors have this problem for many years without getting much worse and people just learn to accept it. If you aren't doing something that requires close position control, it really doesn't matter. It is a pain to have that shaking when it corrects, but I'd wait if I didn't really need close control.

[Rockin' G Ranch]

Thanks for the replys. It happens when the implement is raised whether I'm stationary or traveling. It doesn't do it all the time. Sometimes it may do it for a few minutes then not at all the rest of the day. Some days it does it much more. I can live with it as long it is not making the problem worse (or putting more wear on my system) by not addressing it.

[Alt5600]

Could it be cavitation?

[Soundguy]

Alt5600.. it's doubtfull it is cavitation.. that would happen on the pump side.. not the pressurized cyl side. I think Jinman hit the nail on the head.

The poster is probably seieng a system leakdown and then system regeneration in a position control scheme. Likely sources are relief or check valve, internal gaskets and oings, including the lift piston/cyl.

Ford/NH used a unloading type valve that will do this very thing.. their previous control valve setup pre 53 did the same as well.. it's quite common.

soundguy