Kubota L4701 150 hours rear end stripped gear popping noise. NOW WITH VIDEO

[chim]

I've looked at this thread without being able to sort things out to any extent. This morning I watched his YouTube video and recognized a sound. My L4240 makes what the OP thinks is grinding gears on his tractor.

This happens when I try to move the tractor in a gear that's too high. Example is going up the "step" into the shed in HI range. Generally the front wheels roll up and over easily, but it takes more effort for the rears to climb in. It also happens when jumping on the hydro pedal in HI attempting to go full speed from a dead stop. This is particularly noticeable at lower RPM's.

I made a video of mine a while back. See below. Notice that the loudest noise was when I let off the hydro pedal. I did a full service on the tractor and after replacing fluids and filters the noise went away except as mentioned above. The old UDT2 was discolored and appeared to have been cooked a bit.

Neil Messick made a video concerning a similar noise but that wasn't with a HST trans. In that video it was a normal hydraulic sound.

L4240 HST Noise

youtube.com

 

[#40Fan]

His only made the noise when hitting the brakes.

Yours (chim) sounds like a heat shield rattling around.

 

[GrizBota]

His only made the noise when hitting the brakes.

Yours (chim) sounds like a heat shield rattling around.

Agreed. I’ve listened to the audio in both the OP’s video and this new one. They do not sound similar to my ears. Nor is it a similar action taken taken to result in the audio heard.

 

[fried1765]

I've looked at this thread without being able to sort things out to any extent. This morning I watched his YouTube video and recognized a sound. My L4240 makes what the OP thinks is grinding gears on his tractor.

This happens when I try to move the tractor in a gear that's too high. Example is going up the "step" into the shed in HI range. Generally the front wheels roll up and over easily, but it takes more effort for the rears to climb in. It also happens when jumping on the hydro pedal in HI attempting to go full speed from a dead stop. This is particularly noticeable at lower RPM's.

I made a video of mine a while back. See below. Notice that the loudest noise was when I let off the hydro pedal. I did a full service on the tractor and after replacing fluids and filters the noise went away except as mentioned above. The old UDT2 was discolored and appeared to have been cooked a bit.

Neil Messick made a video concerning a similar noise but that wasn't with a HST trans. In that video it was a normal hydraulic sound.

L4240 HST Noise

youtube.com

That sounds terrible!

 

[chim]

Yes, mine DID sound really awful.

When I listened to the OP's video, I picked up on the sounds the tractor made at 0:14, 1:37 and 2:00. Right or wrong, I thought those were the sounds he was trying to demonstrate based on my interpretation of what he said. The many other times were just squeaky squealy brake sounds that I discounted.

Neil Messick has a short video of a customer''s tractor that makes a similar sound. Although the transmission is different from ours, there are probably some things in common such as fluids being forced around.:

Here's my original post from last year. It's been running fine for 14 months (85 hours) since then:

L4240HST Noise

My L4240HST started making a noise today while mowing. It has made a similar noise in the past, but today it was really loud. It happens when accelerating AND when I leave off the hydro pedal and the tractor slows itself. Previously it made a noise when there was a load on the trans, mostly...

www.orangetractortalks.com

 

[Nicksacco]

Good and useful information for sure.

The part I don't get on the original poster's thread is the weird noise at the beginning of his video - which is NOT the same as when he backs up and hits the brakes. Two different noises. And it sounds as if his rpms are quite above idle.

The weird noise does sound like stripping gears, but is it? Could low tire pressure cause that or is it something loose structurally creaking like creaky floors? It only does it once. Cold hydraulic fluid?

I believe the brake structure of my L35 and his tractor are the same and why his squeaks in reverse has me stumped since both our tractors utilize enclosed wet brakes. How would brakes in lubricant squeak?
Low hydraulic fluid? I would've thought he'd checked that.

You can hear the squeak timed exactly as his foot is on the brake (at first I thought the squeak was in the brake actuating mechanism itself).
Could it NOT be the brake that's squeaking but something moving in the HST when the foot comes off the treadle and the brake is applied?

Oh well, all we have to go on is his video and that's about as good as it gets.

 

[Rdrett]

I wanted to post an update on my tractor, I have had time to use it since the repair.
The brake replacement has fixed the squeaking noise when hitting the brakes and the loud popping noise when hitting the brakes.
‘They must of done something with because the “creep” when releasing the HST pedal and leaving it in the neutral position is a lot better, it creeped 4 times faster before taking it into service compared to now.
The parking brake still won’t hold the tractor back on a hill, it will still roll. The odd part is it sit on a hill for 30 minutes without rolling but all of a sudden it started rolling.
I think the parking brake need’s adjusted, I can push the pedal past all 3 notches on the parking brake.
Does anyone know where I can buy a service manual to get the brakes adjusted properly?

 

[Fordtech86]

https://www.kubotabooks.com/AutoIndex/index.php?dir=Tractor%20Owners%20Manuals/&file=L3301%2C%20L3901%2C%20L4701%20Workshop%20manual..pdf

 

[NCL4701]

I’d still suggest downloading the WSM Fordtech linked. I have that one and have found it to be quite helpful in addition to the OM.

Glad to hear it finally got fixed.

 

[Joisey]

I wanted to post an update on my tractor, I have had time to use it since the repair.
The brake replacement has fixed the squeaking noise when hitting the brakes and the loud popping noise when hitting the brakes.
‘They must of done something with because the “creep” when releasing the HST pedal and leaving it in the neutral position is a lot better, it creeped 4 times faster before taking it into service compared to now.
The parking brake still won’t hold the tractor back on a hill, it will still roll. The odd part is it sit on a hill for 30 minutes without rolling but all of a sudden it started rolling.
I think the parking brake need’s adjusted, I can push the pedal past all 3 notches on the parking brake.
Does anyone know where I can buy a service manual to get the brakes adjusted properly?

" The odd part is it sit on a hill for 30 minutes without rolling but all of a sudden it started rolling. "

That is exactly what my L47 does. I've taken to facing the tractor downhill and rotating the bucket downward with pressure, making it an anchor. I don't trust the parking brake on my machine on any kind of slope.

 

[Nicksacco]

Even though my brakes are working correctly, I still use the bucket as @Joisey mentions when parking on a hill.
The thought of chasing after my machine gives me the chills

 

[jyoutz]

" The odd part is it sit on a hill for 30 minutes without rolling but all of a sudden it started rolling. "

That is exactly what my L47 does. I've taken to facing the tractor downhill and rotating the bucket downward with pressure, making it an anchor. I don't trust the parking brake on my machine on any kind of slope.

I also lower the 3ph with implement.

 

[Joisey]

I contacted Messicks in Mount Joy, Pa and spoke to one of their mechanics. He told me off the record that the parking brake problem we have is common to Kubota HST tractors, as there isn't a set of gears that are mechanically tied to the engine to prevent movement when the engine is not running.

So gents, throw out an anchor and pray when you stop on an incline. Here in WV, everything is an incline.

PS The dry disc brakes on my 680 CK held fine with the parking brake, and that unit weighed about 8 tons. It held so well that if you didn't release the parking brake and tried to take off it would drag the engine down and not budge the rear wheels.

 

[whitetiger]

He told me off the record that the parking brake problem we have is common to Kubota HST tractors, as there isn't a set of gears that are mechanically tied to the engine to prevent movement when the engine is not running.

Did he also tell you that no matter what color the tractor is, if it has a hydrostat transmission, there is no set of gears coupling the rear axle to the engine?

All tractors without a park pawl use a brake to hold the tractor while parked. Kubota does not use a park pawl until the M's and MX series.

 

[D2Cat]

Speaking of that park pawl that holds an automatic transmission in park. Ever park a vehicle, truck or car, on a slight slope and if backing up when starting the engine next time to go somewhere it SLAMS as you move? That's that park pawl doing it's job. You can reduce the slam by putting the transmission in forward gear and move a foot or so, then go to reverse!

My neighbor parks on a slight slope and slams it in reverse every time he drives off.

 

[Joisey]

Did he also tell you that no matter what color the tractor is, if it has a hydrostat transmission, there is no set of gears coupling the rear axle to the engine?

All tractors without a park pawl use a brake to hold the tractor while parked. Kubota does not use a park pawl until the M's and MX series.

No, but having rebuilt automatic transmissions for 25 plus years, I had already figured that out.

 

[mcmxi]

Kubota does not use a park pawl until the M's and MX series.

Check ... and check. I'm not sure that I've ever felt the park pawl on the MX engage but will have to check on that. I park it on relatively flat ground with the loader and rear implement down on the ground so it's not going to roll.