Forum and FAQ: Fendt JCB Massey Vario Gearbox Problem

Forum Boite Vario Fendt Probleme

Forum Boite Vario Fendt Probleme


I repair Vario gearbox Fendt JCB Massey, you can write questions, on this material that I know very well and which is globally very resistant and performing, but like any mechanic, nothing is eternal.

Ask your question about box vario fendt at the bottom as a comment

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fendt vario gearbox reparation tractor

the explanation of variation is not simple:
according to your schema, we’ll say that the vario transmission combines both mechanical and hydraulic energy, and is a constant balance between action and reaction, of the planetary train, epicyclic train:
tractor stopped:
as shown in the diagram, the pump is at zero flow. it is driven by the internal combustion engine via 5 and 2 since planetary 4 is at a standstill (4 is the shaft to the wheels), the hydraulic motors do not have a flow rate and therefore block the shaft (4)
so easier to drive the pump flow rate 0, than the impellers.

movement of the tractor:
hydraulic motor max. displacement, the pump gradually discharges, up to its max. displacement = increase of the hydraulic motor speed. at the same time mechanical dimension the resistance created on the crown (3)
by the pump rising in pressure, allows the epicyclic gear (2) to transmit power from the internal combustion engine to the planetary (4).
the crown is the reaction element of the epicyclic train. the planetary is spinning.
the top shaft (8) transmits the hydraulic power from the hydraulic motors and the mechanical power of the planetary (4) to the wheels, the tractor moves forward.
the power transmission is largely achieved by hydraulics, the greater the resistance to forward movement, the higher the pressure.
when the pump (6) reaches the maximum displacement, the motor’s displacement decreases, which leads to an increase in the speed of the motors. the pump pressure is constant and the useful flow rate will decrease as the motors consume less and less since their displacement decreases towards zero. This decrease in the flow rate at constant pressure will lead to a decrease in power in the hydraulic part. on the mechanical side this will result in a decrease in the speed of the crown (3) of the epicyclic gear (2) which will lead to an increase in the speed of the planet (4). (multiplier effect of the train with entry through the satellite carrier)
The acceleration of the engines and the planetary will allow the tractor to accelerate.
when the motors (7) reach their zero displacement they no longer drive the drive shaft (8) and they do not admit any more flow and thus block the pump (6) as the pump is connected to the crown (3) of the epicyclic gear (2) which will also stop.
so the epicyclic gearbox does not transmit any more power to the pump, (locked crown) so all the power of the internal combustion engine passes through the planetary (2) or 100% of power transmitted mechanically.
configuration at max. speed (50 km)
the parts in yellow = front axle and purple = universal joint shaft, there are also two slow and fast ranges I and II
this system is also with small variants on steyr (new holland case) TVT, CVX. on john deere, IVT.
AND the inventor is for me komatsu, on his bull D155ax-3 hydrau mecanical transmission (HMT) of 1989
and I forgot the toyota prius, with an electric motor instead of hydraulics.

hydraulic VARIO gearbox tractor fendt

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continuously variable transmission tractor FENDT breakdown relief tractor

A continuously variable transmission can be built up from an epicyclic gearbox, by following the following assembly:
-motor shaft coupled to the emitting turbine of the hydraulic converter,
-Planetary planetary coupled to a first receiving turbine,
-crown coupled to a second receiving turbine,
-Satellite carrier coupled to the wheels.
In principle, the stepless gearing is varied by adjusting the flow distribution between the two receptor turbines.


Fendt vario gearbox. The gearbox base is a planetary gearbox, with the motor connected to the satellite gate, the crown to a hydraulic pump connected to a hydraulic motor that drives a summing shaft connected by a gear to the planetary gearbox.
The reduction ratio varies according to the inclination of the pump and hydraulic motor. I would like to know how I could find the gear ratio of the train according to the inclinations of the motor and pump (not the same)

You need to find a relationship between the speed of the pump and the hydraulic motor, probably by comparing their respective flow rates, which depend on the inclination of the plates.
With Willis’s relationship, you have 2 equations, and you can find the third one which is the expression of the transmission ratio.
If I understood correctly, you say that the total ratio is « indeterminate » at a given hydraulic ratio.
I find it very strange… A given hydraulic transmission ratio can correspond to only one total ratio.

The hydraulics only allow variable ratio with a torque converter with very average efficiency, except that there is no variable ratio here. And has a given alpha and beta, the hydraulic transmission ratio is fixed.

In my opinion, the system is made in such a way that the hydraulic part allows the variation of the ratio, while transmitting only the variable part of the movement (variable in + or -).
The mechanical train transmits the constant part.

This is why the hydraulic element 6 can be reversed (angle varying from 45° in one direction to 30° in the other). It is this inversion that makes me talk about element rather than motor or pump (and this is as much for element 6 as for elements 7).

By doing so, the poor performance of the hydraulics (compared to a gear train) affects only part of the transmitted power.

So reduced hydraulic, reduced losses, only happiness…

Then, it is only a simple equation of a system in which, it is not necessary to get stuck in the signs…

The strange thing is that the inversion is done on the shaft outside the mechanical transmission chain, so beta must pass at 0° when alpha passes at 0°… Otherwise block 7!!
It’s a constraint I can’t explain.
Is there a coupling between alpha and beta angles in the control?
I’m not just a scientist, I’m not just a technician.
if I understood your sentence above, the pump can be at zero flow so without any flow, and the motors receive nothing, and block the sprockets they drive, and to meet your demand the pump can be at reverse flow; or reverse.
I would like to emphasize that each element, crown, planetary, and satellite, are very often constrained, and that they release their energy for another element, their energy, when they lose their efficiency, and that they are no longer a priority, but they can be complementary….
for motors 7, just like the pump, from the moment there is a zero
When the engine is full, the system locks up and gives way to another function of the tractor’s drive, which is the end result for this function.
I’m not sure I’ve explained it properly.

I forgot to say, there are 2 engines for the small tractor range but for the high range there is only one engine with a large displacement.

the pump can be at zero flow so without any flow, and the motors receive nothing, and blocks the sprockets that they drive

after the pump’s maximum flow rate has increased, the motors decrease their displacement and thus they will end up at zero displacement at a given time,
so the pump is blocked, but the motor shaft is not blocked (8) and moreover, since the crown is blocked (that which drives the pump) the satellites (thermal) always drive but now the planetary which turns the shaft (8) and thus the wheels via sprockets, ranges and axle, etc….
If there is a heavy load on the tractor’s hook, the hydraulic system can resume and help the mechanical part.
I didn’t insist that the pump works at constant power.
because the pump with max. flow rate and max. pressure exceeds the output
the smallest of these tractors (from 120 to 230 HP) so if the pressure is too high in relation to the flow rate, the displacement automatically decreases
so the accelerator at the floor, which is stopped, has no effect on the thermal.
Another advantage of this system is that the tractor remains in position without a hand brake even with heavy loads, whether mounted or lowered.
Hydraulics only allows variable ratio with a torque converter with very average efficiency
a hydrostatic machine that moves on the road from 0 to 30 km/h the pump flows from 0 to 250l/minute, there is no variable ratio! explain me better so that I understand

6 commentaires

  1. Ping :continuously variable transmission tractor FENDT breakdown relief tractor - Réparation Pompe, moteur Hydraulique

  2. Ping :Continuously Variable Transmission Fendt Operation - In Situ Experts Hydrauliciens

  3. MF7495 Dyna Vt 2008
    Error code 4158 slip transmition
    Oil is clean, I found some green and black rubber peace in filter.
    Tractor moves only from engine 1400rpm.
    What to do?
    Thank you

    • I think i have the same problem When i start driving i got this transmision fault when i drive at 50 km/h and the fault acure the joystick stop working and the transmisson slows down to ca 22km/ often it repeats 3 times i have to stop traktor and restat it and then i often can drive all day as normal. Yesterday the fault acured all the time so i had to drive only whit the clutch, and today It hade no fault but I did only drive an 1/2 hour.Wats the problem?
      The tracktor i a Fendt 714 Vario. 2003year i think.

      • hello

        Your question :

        Je pense que j’ai le même problème Quand je commence à conduire j’ai ce défaut de transmission quand je conduis à 50 km/h et quand le défaut se produit le joystick s’arrête de fonctionner et la transmission ralentit à 22km souvent il se répète 3 fois je dois arrêter le tracteur et le redémarrer et alors je peux souvent conduire toute la journée comme d’habitude. Hier le défaut s’est produit tout le temps alors j’ai dû conduire seulement avec l’embrayage, et aujourd’hui il n’y a pas eu de défaut mais je n’ai conduit qu’une demi-heure.quel est le problème ?
        Le tracteur est un Fendt 714 Vario. L’année 2003, je crois.
        You too only start moving the tractor when the engine reaches a certain number of rpm?
        If I understood your breakdown correctly:
        When you drive at 50 km/h, sometimes the tractor slows down to 22 km/h (brake or freewheel?)
        Then to be able to drive at 50 km/h again, you must stop the tractor completely, switch off the power and restart the engine.
        This can happen several times in a row or not at all.
        I have several questions:
        Does the fault never occur when you only drive with the clutch?
        Does this only happen when you are carrying a load? When you’re empty? Or in both situations?
        Generally, the first time of the day that this happens, how long did you drive?

        Vous aussi le tracteur ne commence à bouger que quand le moteur atteint un certain nombre de tour par minute?
        Si j’ai bien compris votre panne :
        Quand vous roulez à 50 km/h, parfois le tracteur ralenti jusqu’à 22 km/h (frein ou roue libre?)
        Ensuite pour pouvoir de nouveau rouler à 50 km/h, vous devez arrêter complètement le tracteur, couper le contact et redémarrer
        Cela peut se produire plusieurs fois d’affilées ou pas du tout.
        J’ai plusieurs questions :
        Le défaut ne se produit jamais quand vous roulez uniquement à l’embrayage?
        Est-ce que cela se produit uniquement quand vous transportez une charge? Quand vous êtes à vide? Ou dans les 2 situations ?
        Généralement, la première fois de la journée que cela arrive, vous avez roulé combien de temps?


  4. hello

    it is about a tractor Massey Fergusson of approximately 200 horses, I suppose is assembled with vario ML160
    this error code corresponds to code 4.1.58 at fendt
    I know very well the problem, it is after this code defect that arrives at my house vario for troubleshooting or repair
    how long does the tractor work?
    the problem and came gradually or brutally?
    is it worse in high temperatures?
    Give me as much detail as you can and we’ll see how we can help you out.
    apparently you are from Lithuania, that’s right? if not from which country, I work regularly with all Europe, transport is easy, cheap and fast
    vario repair is our core business

    Code d’erreur 4158 transmission des bordereaux de transmission
    L’huile est propre, j’ai trouvé du caoutchouc vert et noir dans le filtre.
    Le tracteur se déplace uniquement à partir du moteur à 1400 tr/min.
    Que faire ?

    il sagit d’un tracteur Massey Fergusson de 200 chevaux environ, je suppose est monté avec vario ML160
    ce code erreur correspond chez fendt au code 4.1.58
    je connais tres bien le probleme, c’est apres ce code défaut qu’arrive chez moi les vario pour depannage ou reparation
    combien heure a le tracteur ?
    le probleme et venu progressivement ou brutalement ?
    est ce pire a chaud ?
    donner moi un maximum de details et on verra comment vous depanner
    apparemment vous etes de Lituanie, c’est bien cela ? sinon de quelle pays , je travail regulierement avec toute l’Europe, le transport est facile, pas cher et rapide
    la reparation de vario est notre metier principale


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