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Thread: John Deere Direct Drive Gearbox

  1. #181
    jd 6820
    Guest

    Re: John Deere Direct Drive Gearbox

    As already posted by cp the selector forks are moved using electromagnets this allows quick and precise movements, something which takes more complex systems when done hydraulically, I would argue hydraulic systems would be more prone to problems especially as the shifting pattern would have to be monitored by sensors, unlike the electromagnet which when shifting is monitored only by the transmission control unit that detects the change in current/voltage as the selector is moved. A far more reliable design, provided the software is programmed correctly.

    As for shifting when in Auto, one would hope that the fact engine load and rpm are measured and used to calculate the correct gear one would assume gear selection is also more often than not correct for the application.

  2. #182
    honest john
    Guest

    Re: John Deere Direct Drive Gearbox

    I have a question for CP.
    It seems the bottom speeds are to fast for some jobs. Is a creap box avaible ?

  3. #183
    DrDunc
    Guest

    Re: John Deere Direct Drive Gearbox

    Quote Originally Posted by honest john View Post
    I have a question for CP.
    It seems the bottom speeds are to fast for some jobs. Is a creap box avaible ?
    No creeper yet. Maybe CP knows more about if/when one available?

  4. #184
    WHF
    Guest

    Re: John Deere Direct Drive Gearbox

    Test drove one the other day, only up the road and back with nothing on the back, so it wasn't the most comprehensive of test, but the gear shifts within range are quick. I started off up the road thinking that they were average, but putting the box into manual and changing up and down like you would on a standard powershift box showed how much quicker the changes were in Auto mode, which I should think most tractors will be driven in 95% of the time.

    Yes JD are hyping it up, but come on, give them a break - no company is going to market a significant addition to their ranges as "Pretty average really, some of you won't like it!"

    From the brief look at the system there are plenty of ways to set the system up so the changes will take place at different places in the rev range so the machine isn't constantly changing between two gears when working at certain speeds.

    I must admit I have driven Deeres for a fair proportion of my working life, and think that they are a good product (not as good as they should be given how far superior they were in the late 80s compared to some brands) but I did spend 5 years sat on Fendts which I thought were pretty spot on, and have driven numerous makes now and then. I'll say straight away that the Fendt vario box is far better than the JD autopower box, but it seems that everyone is comparing the DD with a CVT box which is like comparing eggs with bananas.

    JD have been quite cute in promoting a gear box with some of the benefits of a CVT box, those being the ability for the tractor to decide for itself what gear and engine rpm to run in at a given speed to provide fuel efficiency. But they are also marketing a pretty sophisticated mechanical gearbox which will appeal to a lot of buyers who wouldn't go for an autopower for the facts that: It is totally mechanical drive through the gearbox so there is little power sapped by pushing oil around. It is also a lot more mechanical which just works better in some owners heads. JD have had a few issues with their autopower boxes, just ask Guy (tin hat on), so marketing another gearbox which sits in between the Autoquad and the Autopower will only attract more customers.

    WHF

  5. #185
    cp
    Guest

    Re: John Deere Direct Drive Gearbox

    No creeper yet but there's room for it

    That why there's still the places for the autopower

    And there has to be some difference and that one

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