L3800 HST - HST making noise in High

L3800 HST - HST or Hyd Pump making noise in High

Hi guys, I have 100 hrs on my 2012 L3800. Mowing, Backhoe and loader work, I don't baby the machine but I don't abuse it either.

Last weekend I brought her back from my property about 14 miles away, I do not have a trailer so I took her down the county roads . . 2700 RPM in High gear.

I wear shooting earmuffs when I operate to protect my hearing . . Any way about 1/2 way back I noticed a rattle , not a mechanical kinda rattle like to pieces of metal rattling together . . I got plenty of those just because its a tractor. This seemed to be coming from the right side a bit forward and down low. . . it was speed related and was most pronounced when the tractor was unloading going downhill . . if I let up on the HST pedal just a bit it would get quieter, if I let up a little more it would go away . . on the flats and going uphill it was not there . . It does not sound like the good kind of rattle . . it started out barely noticeable but then over the next couple of miles it became unmistakable but not alarming or obnoxious. If I throttled back 100 RPM it does not do it. I have made this 14 mile journey a half dozen times, this just started. Towards the end of the trip it was intermittent whereas it was constant at the beginning under the speed conditions noted above.

It's not a good sound and I suspect it is related to the hydraulic pump . . Thoughts?? And do I need to get her in the shop . . Warranty expires in December.

Edited to add: The Hyd Fluid is if anything , , slightly overfilled (by maybe a quart and a half, maybe two quarts) when I did a complete fluid and filter change at 52 hrs I was not on a completely flat surface. Did not realize it untill I checked it when I got her home Sunday from my property.

Thanks Bulldog . . I did go over the tractor pretty thoroughly. That is why I am pretty sure it's not something simple like that.

Loader was on the machine and while the noise was occurring I raise, lowered, curled the loader etc . . never made a difference in the noise.

North Idaho Wolfman said:

Was it in 2wd or 4wd?

Could be as simple as the propeller shaft( front wheel driveshaft) rattling, as it moves all the time, even with 4wd disengaged.

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Sir, It was in 2 wheel drive on blacktop for 14 miles.

Bulldog said:

Since you are thinking it's hyd related, did you ever notice any noise before the fluid and filter change?
What kind of fluid and filters did you use when it was changed?

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No Sir, never any noise until that last road trip home from the property at about the 99 hour mark.

I used all Kubota filters and Super UDT2 at 52 hours. The noise is coming from low in the engine area and is loudest on the right side . . like a rattle but more metallic if that makes sense . . louder when the tractor unloads . . down a slight incline . . 2700-2800 RPM in High . . backing off ~slightly~on the go-pedal reduces the noise, backing off a little more eliminates the noise..

Maybe this weekend I will put her on the blacktop and try to make it do it again, then I will put her in 4WD and see if it changes . .

Update:

OK Guys, I took the tractor out today for a spin to try to nail down that noise. It only does it in 2WD, when I put her in 4WD the noise does not occur. It is still not a good rattle. I will be calling the dealer to pick it up tomorrow to take a look at it.

Problem Solved!!

The source of the noise was the tube that covers the pilot shaft to the front wheel drive. The forward part of the tube is secured by a rubber grommet that plugs into a larger tube at the rear of the crankcase oil pan.. This grommet had backed out of the front tube allowing it to rattle loudly (and alarmingly I might add . . my neighbor heard the sound and said it sounded like gears getting chewed up . . he is a heavy equipment mechanic . . .)

I pushed the grommet back in place and the noise went away until the grommet backed out again. Then I secured the grommet with some black RTV.

Glad it was something simple and not expensive.