Combines John Deere IVT Transmision

[lexi]

I drove a couple of IVT-equipped tractors (6420, 7520 and 7710). We had a 7710 last spring and I can tell you that this transmission can make a real difference compared to a powershift. However, I would suggest you to wait a little longer before buying an IVT equipped tractor because JD still have some problems that need to be fixed on this transmission. Here in Quebec, JD dealers sold a lot of 6420IVT for snow removal, but the snow removal companies had a nice surprise when they found that when the weather is too cold, the tractor doesn't move!!!!!!!!!! I would suggest you to ask for a serious and long enough test drive to be sure that the transmission really works on those big tractors.

 

[dakota]

Fendt has such a transmission on the market since 97 with a 300hp engine infront of it. I wonder how similar the design of those IVTs from different manufacturers is.

 

[jalopy]

A much simpler but similar transmission has worked very well for almost 40 years, made by Sunstrand, or more commonly known as the IH hydro tractor.

 

[Silver_Shoes]

Hi, I will try to answer the similarities question right quick. Fendt's transmission is a full CVT tranny, unlike the deeres which is a IVT linked to a powershift transmission. The reason deere has to link it to a powershift is because the Fendt technology is patented and I will try to explain the best I can. Fendt has patented the technology of gettting a 45 degree angle on the pump shafts which gives them the ability to have a full range of speeds without linking to another transmission, unlike the Deere transmission which has 30 degree shafts. The reason Deere is smooth shifting is because the transmission is linked to the fuel system threw electronics which adjusts engine rpm to take out the jerks of the shift of the powershift behind the IVT. Deeres tranny is 88% efficient compared to Fendt being 98% efficient. I know most ppl have a good taste in their mouths about Deeres equipment but really most should give a little more attention to the other colors. There is too much new technology in the market today to be color blind I guess is all I am saying. The Fendt transmission is so simple that they dont even split the tractor to remove the transmission if and when it has a problem. Seriously this Fendt CVT is an amazingly simple and effecient transmission. Agco tractors are getting it now and rumors are abound about which next division is going to have it. The mechanical and powershift trannys are obsolete, as is the hydrostat. And the CVT IS NOT A HYDROSTAT. Not trying to upset anyone with these comments, just revealing some info.

 

[tedbear]

I have a friend who purchases a 7820 with the IVT. In fact I went with him and watched the final assembly. We were the first "Gold Tour" group for the 7X20 tractors at Waterloo. He had to wait a bit for the delivery as there were some last minute changes at the factory. I guess this might be expected considering the considerable changes from the "TEN" series. I have not driven his tractor under field conditions for long periods of time, but he is very happy with the Tractor and the IVT. He has not used it a tremendous amount but it is main tractor and was used in a variety of applications including Fall Tillage. I understand that the IVT is only choice on the 7920 and is an option on others. He was telling me last week that he had done some experimenting with the IMS (Implement Management System) and how it can interact with the IVT. Apparently the IMS can return to a transmission position in a fashion somewhat similar to IMS in the powershift transmissions on the 8XX0 series. Comparing the IVT in the 6XX0 series and the 7XX0 series may not be a good comparison as I understand there are considerable differences. I believe the 6XX0 series is coupled to a four speed powershift while the 7XX0 series is coupled to a two speed powershift. I was told that the 7XX0 is an American design while the 6XX0 is German. I saw a cutaway of the Fendt transmission at a farm show last year. The fellow was doing his best to explain it to us but the language barrier and complexity left me confused. As I understand it,the Deere transmission has a Planetary assembly that is "underdriven to overdriven" at various rates to achieve the variable ratios. Unlike other Planetary arrangements where the assembly is either free or locked providing two ratios, this system is variable by driving the assembly with hydraulics. Considering the efficiency: at certain points within the range the transmission is essentially mechanical, at other times it is more hydraulic so the efficiency varies. In order to provide the entire range of ratios necessary this portion of the transmission is connected to a more conventional powershift unit. The electronics controls the various components including the engine to make the entire package work together smoothly. Efficiency is a relative term. If we want pure mechanical efficiency, other straight gear arrangements are more efficient. If we view efficiency from an overall standpoint of operator comfort and productivity the definition changes.

 

[buckshot]

If both trannies use a combination of hydraulic pumps and a planetary gear, how do you come up with a ten percent efficiency differenceIJ

 

[jalopy]

And if one of the main components is an axial-piston-pump (and_or motor),then what exactly does the term "hydrostat" meanIJ Sure it may have electronic modulation and coupled to a powershift, but are we getting brainwashed with a new word (IVT),charged another $20,000 for it, and left thinking we have some kind of brand-new technology when in fact it is just a little bit different breed of hydrostat with the same effeciency and cold-weather issuesIJ I'm not trying to start an argument, I'm posing some questions and am confused.

 

[Silver_Shoes]

Ok, if you put an engine in front of one transmission and run it and take the efficeincy ratings of that setup, and then compare it to a system which is powering 2 transmissions you will soon see the difference in efficeincy. Its just more moving parts, more friction, more heat, which consumes more energy.

 

[Silver_Shoes]

No arguement taken, I really understand your quest for knowledge on this system. When I first heard of the Fendt fluid drive, I thought thats got to be junk because everyone knows that fluid drive is less efficent than mechanical drive rightIJ Well to my surprise I went to school on this CVT transmission and learned that basically they are taking hydraulic motors pumping against each other to provide mechanical drive. The way they do it basically again, is in the fact that lquids do not compress, therefore it becomes mechanical power with is constantly variable with the position of the pump shafts controlling the flow of power. Im not the engineer of these but I do find something very intriquing about a transmission I previous figure to be some junk techno. I cant stress how simple the new variable transmission is in the Fendt, but like you I wish I could afford one. Of course on overhaul job on my powershift and I might be able too and at the same time not put up with the power jerks of my transmission.

 

[CharlieC]

I saw a 7820 with IVT at this weekends ploughing world record .Pulling a sled in the tractor pull it was not good at all.Did not go far at all before it bogged down and came to a halt with all wheels just scratching.