New L3901 Hissing Noise

[jdsande3]

I just bought a new L3901 and I get a hissing sound/noise near the transmission area (below gage cluster) at idle after the tractor has warmed up. When I first start it, no noise there, however, after using it a few minutes I can hear a hissing noise only at idle. Could it be a relief in the hydro system dumping fluid back to the reservoir? Is this normal?

Any help greatly appreciated!

 

[mdhughes]

Is it a HST or DT?

Did it do it when you first got the tractor?

Have you done any mods to the tractor?

Does it do it with and without the backhoe connected?

 

[jdsande3]

Its HST, and no mods to tractor. The backhoe is connected, I've only disconnected it once, and don't remember then if it did it or not. Think it could just be pressure returning from backhoe?

I think it has made the noise since new, I can't be 100% sure as I was excited to be using it when I got it.

 

[bambam31]

If I don't drive my tractor for a awhile I always think I hear a strange noise. Do you only occasionally operate your tractor?

 

[fishbulb]

I have a (almost) new L3301 HST that does this too. It's got 60hrs and it's always made the noise after I've been working it hot for a while (mowing or etc.). When I idle down to get started putting things away is the only time I hear the noise. The exhaust noise covers it up at higher rpm so I can't tell if it changes with engine speed or etc. Definitely sounds like fluid rushing through a fitting or hose. I try to avoid extended idling for the sake of the DPF so I do not know if the sound goes away if left to idle for a while.

I recently did the 50hr service so it has all new OE filters and 1gal. of SUDT2 top-up after filter change. No change to the sound after service.

Since the noise has always been there as far as I can recall, I haven't dug into it so far to try using a mechanic stethoscope to see if it's really the transmission, or just the valve-body on the side under the foot rest. I do have a FEL so there's an extra power beyond plate stacked on my main valve body, much like your backhoe kit probably has.

 

[edritchey]

I have a L3901 and never noticed any hissing sounds that I can remember. It has the normal whining of the hyro but that's it. I'd beinterested in knowing whats causing that sound on your's. I very rarely let mine idle though.

 

[troverman]

My MX4800 (17 hours on it now) also makes this hissing sound with my foot off the hydro pedal. Any slight application of forward or reverse (not even enough to make the machine move) causes the hissing to instantly go away. I'm assuming normal.

 

[jlenz0213]

Did anyone ever figure this out? I have a new 3902 that does the same thing

 

[mikester]

Tinnitus - Symptoms and causes

www.mayoclinic.org

Sorry bud, there is no cure

 

[jlenz0213]

Is this something all the new ones do or just certain ones? Could this be the turbo?

 

[retired farmer]

My L3301 has never hissed at me, unlike the outside cat that hangs around here. Also I found a snake coiled up on the tank one day, It didn't live long enough to hiss. I hate snakes.
rr

 

[Cathy Liebchen]

Sounds normal