Does anyone know if all L4600 HST tractors are equipped with "Featherstep HST" ?

[ken erickson]

Title pretty much sums up my question but here is the back story.
I have a good friend down in MO that has had his 2014, roughly, L4600 at a nightmare dealer for the last 6 months. I am not one hundred percent sure what year he purchased the tractor but I do remember him telling me it was the last year before that sized HP tractor from Kubota would require Regen and DPF(diesel particulate filter).

Six months ago he said the tractor lost almost all forward and reverse action, every other function worked as it should. He took it in to the dealer he purchased it from, just out of the 6 year power train warranty.

They fiddle farted around for weeks, finally split the tractor and replaced some part, not sure what, I have not seen any kind of invoice. After they dropped it off he said the tractor would move forward and reverse but was very much reduced on pushing power, when using the bucket for example. He has over 400 hours on the tractor and is very tuned into how things run and would bet he knows the tractor is not working correctly. All other functions seemed to work as they should.

So, in the meantime the dealership was sold. The tech said he would "turn up the pressure", lol, and that should fix it. Well that never happened. Now the tractor is split again with the new dealer saying they damaged some parts when the tractor was put back together. Now they are telling my friend, they are waiting on parts to fix the tractor , but due to not having all the paperwork completed with Mother Kubota they are not officially a Kubota dealership and not able to order parts from Kubota, at dealership pricing.

Long back story and thanks for reading my rant, now to the question. I want to help him out as far as knowledge and I told him I thought his tractor used servos to control the HST transmission, called Kubota Featherstep HST. Do all the L4600 HST's have this feature? In my mind I was wondering if so, did the dealership do a diagnostic on the servos to rule them out before splitting the tractor.

Thanks for reading along and thanks in advance!

 

[rbargeron]

Not sure this is responsive to your question - bet here goes: (full disclosure - I don't know much about HST's really - but think they are intersting.) For a dealer to not have much experience inside one is not unusual - they are historically near-bullet-proof if oil service is maintained. A tractor's dry disk clutch can fail - but the HST unit itself rarely does.

In Kubota's Illustrated Parts Lists, the model L4600H is the one with HST - others have gear transmissions. The HST transmission itself is similar to the ones used on the earlier Grand L10 models - having an all-mechanical hydraulic regulator that sets direction and speed of travel. Pedal position establishes a desired speed and the valving self adjusts to accomplish it. It was used on L4600's from around 2011 to 2014 - and later on other models. Starting with the L4740 the HST's on Grand L40 models use solenoid valves for electronic control of direction and speed. Refinements have been added for auto-downshifting under load, stall-prevention, etc. and keeping the engine in an rpm range that better controls emissions.

Not sure where the "Feather Step" name comes from - maybe to contrast their lighter pedal force compared to other tractors with pedals directly connected to the swashplate, a design that's ok for small engines but gets harder to deal with as engine power goes up. Kubota BX and B pedal are direct.

 

[ken erickson]

Not sure this is responsive to your question - bet here goes: (full disclosure - I don't know much about HST's really - but think they are intersting.) For a dealer to not have much experience inside one is not unusual - they are historically near-bullet-proof if oil service is maintained. A tractor's dry disk clutch can fail - but the HST unit itself rarely does.

In Kubota's Illustrated Parts Lists, the model L4600H is the one with HST - others have gear transmissions. The HST transmission itself is similar to the ones used on the earlier Grand L10 models - having an all-mechanical hydraulic regulator that sets direction and speed of travel. Pedal position establishes a desired speed and the valving self adjusts to accomplish it. It was used on L4600's from around 2011 to 2014 - and later on other models. Starting with the L4740 the HST's on Grand L40 models use solenoid valves for electronic control of direction and speed. Refinements have been added for auto-downshifting under load, stall-prevention, etc. and keeping the engine in an rpm range that better controls emissions.

Not sure where the "Feather Step" name comes from - maybe to contrast their lighter pedal force compared to other tractors with pedals directly connected to the swashplate, a design that's ok for small engines but gets harder to deal with as engine power goes up. Kubota BX and B pedal are direct.

Thank you for that information!

This is where I got the term Featherstep HST. I do not know how accurate this information is however. That is part of what prompted me to post here asking.

For extra control and operator comfort, the pedal gets what Kubota calls Featherstep HST, which uses a 44.5 cc hydraulic servo to increase pedal responsiveness. Cruise control is also standard

2015-kubota-l4600-hst-review-1716

 

[N3BP]

My 2001 L3010 has the featherstep HST, so I'd have to assume it was standard from that point on on the Grand L's. I'll be honest when I say I really enjoy it compared to the notcyness of a mechanical HST. Attached is an article from my L3010 dealer guide talking about the system a little. This was back in September of 98, so I'd have to assume the system has been refined and updated since then.

 

[MapleLeafFarmer]

it was a marketing word

 

[ken erickson]

This might be a stupid question but the L4600 is not considered a Grand L is it? From the pictures my friend sent me it seems more in line with my L2501 as far as creature comforts.

 

[lugbolt]

L4600 was the largest standard L series. It was not a grand L, although the basic transmission design is really the same as the grand L's were.