3-Point Hitch 3-Point Hitch Not Lowering

Charles Billings · Oct 30, 2009

Three to four times over the last couple of months I have been confounded by the 3-point hitch on my NH TC45DA not lowering. This has not happened with an impliment on, but rather when I am in the process of changing impliments. The last time I was taking off the KKII tiller and putting on a log splitter--pushed the lever all the way to down, but the hitch didn't descend beyond about half way. Tried moving the lever serveral times, still same result. I pulled the tractor away from the impliment so I could get a better look at things, tried it again, and this time the hitch went all the way down with no trouble. I proceeded from there to hitch up the splitter, moving the hitch as necessary to get things aligned, and again no problems. Any ideas what is happening? The hydraulic fluid reservoir is full.

kennyd · Oct 30, 2009

There is a thing called a ROD valve (rate-of-drop valve), usually a knob under the seat that determines how fast a implement drops when the rockshaft lever is pushed forward. If this valve is to far closed, especially when there is no weight on the 3PH then the arms won't drop.

jinman · Oct 31, 2009

Kennyd is correct. The adjustment knob is in my picture below. It's just below the grey seat adjustment knob in the U-shaped cutout of the floormat (small black knob with white letters). It may be adjusted just a bit too slow and be causing your arms to stall downward when there is no load.

Charles Billings · Oct 31, 2009

Kennyd & Jinman, I was hoping to hear from both of you. I am sure this is it, but I couldn't diagnose it myself. It just seemed strange that it had no problem picking things up or lowering with weight, but it did have problems lowering when there was no weight. This is why we pay you both so much for your trouble shooting. Seriously, thanks and thanks!

JC-jetro · Oct 31, 2009

Charles,

Picture below is pretty close to what you have on your 3 pt lift system. It shows the hyd lift piston head. The middle hole and one to the left of it where the hyd flow comes to the lift cylinder pushing the piston. The return path is only from the center hole. Right at a center is the needle valve (conical shape) that regulate the flow back to hyd reservoir. clock wise rotation and conical valve restrict the opening hence slower discharge flow. Counter clock wise rotation of the knob translates to less restriction hence faster drop.The hole in the middle has a check ball so only works to lift the piston. The very last hole all the way on the left is shock release port so your piston seal would not damage.

JC,