Here is what the L4456 Ground Pressure Relief (to be referred to as GPR moving forward) system is/does. This is not an uncommon system with other equipment and it does serve a purpose. For those in snow country all the articulated sidewalk tractors you see like Trackless, Holder, McClean, Steiner, Ventrac etc that run snow blowers, brooms, snow blades etc down the sidewalk, all of these machines have this system. Some refer to it as a weight transfer system because that is what it is.
Without this, what you have is either #1) putting the attachment down on the ground (or where ever you put it) and the hydraulic system is rigid, it stays in that spot, or #2) you put it in float which is just like your loader bucket going in float, it relies on the weight of the attachment to keep it on the ground.
The problems with either 1 or 2 that GPR solves is with -
#1 if the attachment comes up to a change in elevation or contour, the attachment will either skim over a depression or drop until the front wheels reach it which at that point the attachment out front may now be at a different elevation riding on the ground. This will cause the front wheels to lose contact with the ground taking away all ability to steer. Of course the operator can make adjustments on the joystick but this will be choppy and inefficient. It also creates excess wear on the leading edges by putting the full weight of the tractor on them.
#2 if the attachment is in float, it will take the path of least resistance so if it comes up to some hard pack blowing or plowing snow, or if you have a flail and it comes up to some heavier, thicker brush, it may ride up over the top of it, not letting the edge cut out the hardpack or cutting down to the ground on the flail. If you've ever tried to drive forward with an attachment in float, whether it's on the loader or on a hitch up front, you know how ineffective that is. It wont be long until your tractor hits some resistance and the front end rides up. The float function, on about any machine, is not designed to push forward with as a rule of thumb.
With GPR there is a dial and gauge in the cab that allows you to dial in the level of down pressure you want at any point between #1 (no float) and #2 (float) meaning at it's fullest rigid setting it will act like you don't have it in float and at the other end it will act just like it's in float. In-between these two spots you will find your sweet spot. Let's take scenario #1 - when the attachment hits that hard pack, or you go over a depression or hit a high spot, it will have down pressure but not so much (depending on where you have it dialed in to) that it will cause the front tires to break contact, still giving you the ability to steer and control your machine as well as following that contour down into a depression. In addition to giving you the ability to maintain control of your machine and limit excess wear on your edges, you'll also be more efficient in scraping the snow or whatever application you have. This will be far more effective than running it in float. If you find the attachment is riding up when you don't want it to, increase the down pressure. If it's riding up, decrease it. I believe that the GPR function can be shut off entirely allowing you to us the tractor like it would if it didn't have it.
If you have a long flat driveway or parking area or whatever it is that you are blowing the snow off of, you maybe don't need GPR. if your areas are uneven and inconsistent, it will serve you well and you will not regret the extra $35ish per month it costs you.
The other benefit GPR will give you is when transporting the attachment it will give you a level of cushion when traveling at speed. Rather than being rigid sitting out in front of the tractor and each time you hit a bump it causes undo harshness and shock on the attachment, quickhitch and spikes in the hydraulic system, it will help absorb this. It's not as effective as ride control (KSR for [AFFILIATE='1, nofollow=true, newwindow=true, title="Kubota"']Kubota[/AFFILIATE] fans) with an accumulator but it sure is better than nothing. Just a side benefit, not that this is a big problem.
I've been with a [AFFILIATE='1, nofollow=true, newwindow=true, title="Kubota"']Kubota[/AFFILIATE] dealer for 18 years and in the industry for 32 years so that makes me one of those dealership personnel that has questionable honesty and "expertise" such as IchabodCrayne refers to. Over that 32 to years in the industry, I've been in sales with 5 different dealerships (Ditch Witch, Case CE, Caterpillar, JD and Kubota/Bobcat) and can honestly say that each dealership strived to have a reputation of integrity. These dealerships die without repeat business and their goal is to help their customers be efficient and profitable. THAT is what makes them money, not by tacking on unnecessary add ons to your tractor. We do not change modes when we go from doing business with the City of Such and Such or Bob's Premier Property Service to the everyday home owner, rancher or farmer. Granted, like every business or aspect of having to deal with people, there are some bad apples. I've seen these guys come and go over the years, dealerships will weed them out pretty quickly and not tolerate that. It get's tiring coming on here and seeing so many people speaking of the dealerships like they are snake oil salesmen. I will agree that some manufacturers, I might even say especially Kubota, could do a better job of promoting and explaining their value added features and options. Even to this day I think [AFFILIATE='1, nofollow=true, newwindow=true, title="Kubota"']Kubota[/AFFILIATE] is missing the boat on promoting their auto hitch system, something that no one in the compact tractor business has.
I hope this helps.
