4720Ch Hydrostatic Issues

[ceaster]

Hi All,

I have a 2019 4720Ch and I'm noticing an odd issue with my hydrostatic transmission. In High or Medium range, the pedal will sometimes decide to push forward or backward when I let off the forward or reverse pedals. In High range, if I don't have the machine really revved up, it will grab and slam violently into reverse if I start to push the pedal, even with the built in throttle linkage to the pedals, which causes a stall.

I have tried tightening the tension spring (to the point where it's uncomfortable) for the pedals and I have repeatedly tried adjusting the neutral shaft position and nothing seems to work.

I would expect when I left off on the pedals, on an incline or not, for the machine to stay where I left it and I would not expect high gear to react so different minus bogging down if not enough power.

Does anyone have any ideas outside of the tension spring and neutral shaft adjustments? (I should also mention that it doesn't decide to stick with one direction, sometimes it decides to go forward, and sometimes it decides to go backward when I left off, even if on flat ground).

 

[Aquamoose]

Mine is a 3520h so it may not apply to you but one time, the spring responsible for putting tension on a roller lever broke and the pedal would fall either way and thus, the reactor would move. Spring replaced and the pedal reverts to neutral when my foot is lifted off.

Is yours the same way?

 

[ceaster]

Mine is a 3520h so it may not apply to you but one time, the spring responsible for putting tension on a roller lever broke and the pedal would fall either way and thus, the reactor would move. Spring replaced and the pedal reverts to neutral when my foot is lifted off.

Is yours the same way?

Thank you for the reply. It does have a tension spring still in tact, if I tighten it more, the pedal becomes more stiff and it fatigues your legs keeping it depressed, but even fully tightened, it appears like it's returning to neutral from the tractors perspective. The neutral light illuminates, but the crawling either direction still seems to happen.

 

[claggstractors]

Just finished a 3510h with the same issue. Had a loose set screw on the coupler that goes between the control shaft from the pedals to the hydrostat. This coupler is inside the transmission house and had to pull the dash loose to get it up out of the way of the plate on top of the housing. Have a bad feeling cab models will be even more "fun".

 

[Takman]

In my experience and according to Branson this is "normal" for the machine if it's not reved to the green zone on the tach. Had a customer run into his barn while hooking 3pt equipment up in 3rd range and low rpm. Broke out rear cab window but all that matters is no one was hurt.

We were able to recreate the pedal sucking to the floor and machine taking off....obviously you should be in 1st range when hooking up equipment, but I didn't think this should be considered "normal" either.

 

[claggstractors]

In my experience and according to Branson this is "normal" for the machine if it's not reved to the green zone on the tach. Had a customer run into his barn while hooking 3pt equipment up in 3rd range and low rpm. Broke out rear cab window but all that matters is no one was hurt.

We were able to recreate the pedal sucking to the floor and machine taking off....obviously you should be in 1st range when hooking up equipment, but I didn't think this should be considered "normal" either.

Branson's definition of "normal" can drive a man insane. But in my experience, ALL brands leave something to be desired in the service department to the experienced and well read mechanic. Have a feeling we could trade some pretty good "war stories".

 

[ceaster]

In my experience and according to Branson this is "normal" for the machine if it's not reved to the green zone on the tach. Had a customer run into his barn while hooking 3pt equipment up in 3rd range and low rpm. Broke out rear cab window but all that matters is no one was hurt.

We were able to recreate the pedal sucking to the floor and machine taking off....obviously you should be in 1st range when hooking up equipment, but I didn't think this should be considered "normal" either.

I usually hookup to 3-point in low gear for precision, but I do end up in high range going to the fuel station. That's crazy if it would be normal. Having the throttle linked to the pedal would be super misleading in that case. Sometimes it sucks the pedal down and gets caught in a loop of slamming it forward then backward rapidly. It's a major safety issue to me. Every tractor I've driven to this point would just bog down and die or whine loud, but never try to force a rapid take off like that. Because of the Economy PTO, sometimes I mow in high range so I can pick up a little speed without increasing the RPMs as well (that one may be frowned on, but the speed you can mow at with economy would be a joke otherwise).

I got totally off subject. So you said you could recreate it? Does this happen on all of them or just once in a while to a machine?

 

[ceaster]

Mine is a 3520h so it may not apply to you but one time, the spring responsible for putting tension on a roller lever broke and the pedal would fall either way and thus, the reactor would move. Spring replaced and the pedal reverts to neutral when my foot is lifted off.

Is yours the same way?

It has a spring, which I've tried tensioning more, and loosening more , they almost always return to neutral and the read out on the panel says neutral. It also has a cam you can use to adjust where "neutral" is. It also has a damper, but it seems to be fine. On occasion it will stuck because there's no lubrication system for the pedals and I have to spray penetrating oil on the pedals. None of which corrects the odd behavior I'm seeing. I did disconnect the tension spring altogether once and the pedals did flop any direction easily like you described (also if you try that while it's in gear and running, bring a change of undewear).

 

[Takman]

I usually hookup to 3-point in low gear for precision, but I do end up in high range going to the fuel station. That's crazy if it would be normal. Having the throttle linked to the pedal would be super misleading in that case. Sometimes it sucks the pedal down and gets caught in a loop of slamming it forward then backward rapidly. It's a major safety issue to me. Every tractor I've driven to this point would just bog down and die or whine loud, but never try to force a rapid take off like that. Because of the Economy PTO, sometimes I mow in high range so I can pick up a little speed without increasing the RPMs as well (that one may be frowned on, but the speed you can mow at with economy would be a joke otherwise).

I got totally off subject. So you said you could recreate it? Does this happen on all of them or just once in a while to a machine?

If you have the machine at low RpMs and 3rd range, yes all of them I've tried will occasionally take off. I think it has something to do with the auto rev feature being tied into the hydrostat system.

That said it's really situation you should NOT put a machine in.

 

[Slowpoke Slim]

Ceaster,

I have never experienced what you are describing at all. I would also say that I doubt very much that most of the Branson owners on TBN have experienced what you describe.

Other Branson owners sound off here and state whether or not you've experienced this "normal" thing that Branson somehow knows all about, but yet keeps secret and unable to fix.

I would take it to your dealer and have them look it over. If your dealer can't locate the source of the issue, have them talk directly to Branson USA about this.

Despite some random person's internet claims that this is "normal" or not, I would say that it is not normal.