Whining noise coming from front of tractor, can't seem to identify the source

STx · Jul 21, 2016

I have a New Holland TC40DA. Recently, it's started making a whining noise somewhere in front of the operator platform only in forward and only when turning left or going straight. It's consistent when turning left and intermittent when going straight. I had my wife walk next to the tractor while I was driving to see if we could identify the source but, she wasn't able to pinpoint it.

I did have a little bit of a bend in the rod tieing the 2 front wheels together for steering that was causing it to rub on one of the front axle bearing housings, that's been straightened out and it's all clearing now. I've removed and cleaned all the zerks I can find on the front end to be sure they were passing grease and have hit all them with grease and I've checked the fluid in the front differential and both wheels, all are clean and full.

The only issue I still see at all is a slight bend in the ram for the power steering cylinder but, I don't see it leaking any fluid past the seal so I don't believe it's the source.

I don't know what else to check. Does anybody have any suggestions at all? I have an independent local shop that is good and reasonably priced but, I'd rather fix it myself if I can. That said, if I can't figure this out in the next couple of days, I'll be dropping it off Monday morning.

Turbys_1700 · Jul 21, 2016

Is your tractor 4WD? If so does it do it when 4WD is engaged only? Hydrostatic or gear drive? How many hours on the tractor? It would help if you could post a video with the tractor running and the sound it makes. Don't know how to do that unless you link it to YouTube perhaps?

STx · Jul 21, 2016

It is 4WD hydrostatic. It doesn't matter whether or not the front wheels are engaged.

Here's a video, sound is pretty apparent.

Tractor noise - YouTube

Ford850 · Jul 21, 2016

It sounds like one of your hydraulic lines vibrating and coming in contact with plastic or metal. Try to touch each of them to see if you can identify if one is the culprit.

Also - how did you bend the connecting rod and the power steering cylinder?

Leejohn · Jul 21, 2016

Sound more like the HYD pump to me.

STx · Jul 21, 2016

There was one supply line that the bracing had come loose on, I tightened it and it seemed to help some, it's still there but not as consistent or loud.

The main hydraulic pump was replaced about 50 hours ago. I guess it's possible it could be the power steering pump, the noise doesn't seem to be coming from there though. I don't think it would be the HST since it only happen going forward and turning. That kind of makes me thing it's not the power steering pump either.

CCWKen · Jul 21, 2016

Might be your steering valve. ???

Bent rods can over stress it. I'm not sure if there's a bypass valve in it but that's what it sounds like..

STx · Jul 21, 2016

There is an adjustable relief valve for the steering. The sound seems to match ground speed though, meaning the faster I go the more pronounced it becomes.

CCWKen, what part of S Texas are you in? I'm in Duval County, about 15 miles West of Alice, just outside San Diego off 44.

This is the bend in the steering cylinder, it's more of a bow really.

CCWKen · Jul 21, 2016

I live about 3 miles outside of Lytle which is about 25 miles SW of San Antonio. I'm in the "point" of Atascosa county.

The sound should match engine speed since it's a pump that feeds the hydraulic steering valve. Noise that matches ground speed would make me think it's gears, bearings or hydro-trans. The sound sure imitates a hydraulic release valve though. Are you sure all the control valves are centered?

Added: That bend is enough to pitch the piston sideways and cause a pressure leak to the opposite side. Might even cause the piston to seize in the cylinder and score it. You should get that fixed, pronto.

STx · Jul 21, 2016

I hunted on a ranch in McCoy near you a few times with one of my vendors, it's pretty country with some great deer. One of the hunts I was on another hunter shot a buck that taped out at 249 or so. I watched a buck that same morning that would have beat it easily, it was the biggest deer I've seen in my life. It was on the neighboring property though and never did cross the fence. His harem would come over but he hung out in the brush line on the wrong side of the fence.

There's a hydraulic shop in Alice, I was planning to take that cylinder off and see if they could repair it. I don't have any idea how the tie rod and piston got bent like they did. I don't remember doing anything that would've caused it recently.

I thought gears or bearings also, everything was/is well lubed though. It's frustrating that it only happens when the tractor is moving, it makes it very hard to find the source, especially when I'm here by myself. Wife went to Houston Tuesday and won't be back until probably sometime next week.