MF Dyna VT problem

[Farmer666]

Hello! I have Massey-ferguson 7480, 2007, 5950hours. Transmission is Dyna VT and i have problem with that. I have readed all topics in this and all other forums searching knowledge of this fault, but i didnt find that. Some post are close.

Problem. When i shift direction lever example to forward-Mode, nothing happens. Only N-sign start to flickering in left screen panel. Same thing when i move lever to reverse, nothing happens, only flickering N in screen.

Sometimes tractor work well, propably several hours. Few times when i drive tractor normally in field, whit pedal-mode, it suddenly turns stick-mode itself and speed grow, a lot! Scary things.

No fault codes and stick-mode, hare/tortoise, transmission, clutch is calibrated several times, succesfully. Hare/tortoise working well.

Any ideas?

(im from finland, so english is not my strongest skill)

 

[Chae1]

@Dave b

@davidroberts30

 

[davidroberts30]

To me sounds like the shuttle lever is faulty

 

[Bumble Bee]

Have you tried calibrating the stick (the one in the armrest). Sounds like it is getting a signal from the stick that may be changing it from pedal mode to stick mode?

 

[davidroberts30]

Have you tried calibrating the stick (the one in the armrest). Sounds like it is getting a signal from the stick that may be changing it from pedal mode to stick mode?

The fwd/rev lever will do that too

 

[Cowabunga]

It needs to be connected to a dealer's laptop but I suspect that it is either an issue with the actuator or with the wiring. Could be as simple as an Earth [Ground] issue. The actuator is the part that sticks out at the top right of the gearbox and has the manual shift emergency-use nut on top. The one where the handle fits when passed through the available hole in the floor. Maybe try leaving the shuttle lever in neutral and use the handle to see if it works without the electronics. You will probably find the handle stowed in the battery tray. If that works, it should rule out anything in the transmission apart from the electrical part of the actuator and everything electronic up the line in the cab.
Simple things first. Check all earth points at the back and front of the cab and chassis for tightness and good contact, and that the alternator outputs 14V.

 

[Farmer666]

To me sounds like the shuttle lever is faulty

I am thinking the same. I have to check this.

 

[davidroberts30]

I am thinking the same. I have to check this.

Either faulty or the wiring in the loom up by steering wheel is rubbed through

 

[Farmer666]

Have you tried calibrating the stick (the one in the armrest). Sounds like it is getting a signal from the stick that may be changing it from pedal mode to stick mode?

Yes, i have calibrated the stick also. But thanks for good question!

 

[Farmer666]

It needs to be connected to a dealer's laptop but I suspect that it is either an issue with the actuator or with the wiring. Could be as simple as an Earth [Ground] issue. The actuator is the part that sticks out at the top right of the gearbox and has the manual shift emergency-use nut on top. The one where the handle fits when passed through the available hole in the floor. Maybe try leaving the shuttle lever in neutral and use the handle to see if it works without the electronics. You will probably find the handle stowed in the battery tray. If that works, it should rule out anything in the transmission apart from the electrical part of the actuator and everything electronic up the line in the cab.
Simple things first. Check all earth points at the back and front of the cab and chassis for tightness and good contact, and that the alternator outputs 14V.

Thanks a lot. I mean it! I have to check all the wirings under the cabin too. Transmission works well with manual "shifting nut", so its have to be electrical fault. Do dealers have computer programs in these old masseys? My dealer give me only calibration brochures, because driving tractor to them is more or less difficult because the fault.

 

[Farmer666]

Either faulty or the wiring in the loom up by steering wheel is rubbed through

I have to check this, wiring too. New lever cost about 400-500eur here, so i have to be sure before i buy that

 

[Browndog]

Do you get the neutral problem when you start up and release handbrake??

 

[ccp contracting]

Its not something simple like the actuator on the gearbox gummed up with dirt and crap.

 

[davidroberts30]

I have to check this, wiring too. New lever cost about 400-500eur here, so i have to be sure before i buy that

 

[Farmer666]

Do you get the neutral problem when you start up and release handbrake??

Hello and thanks for message. I have been working long days whit my excavator, so thats why my reply take so long But i get problem this way too, Browndog.

 

[Farmer666]

Its not something simple like the actuator on the gearbox gummed up with dirt and crap.

I try to powerwash hole transmission and everything else under the tractor. But still is possible to have dirt in wrong place.

 

[Farmer666]

View attachment 994284

Big thanks for this picture. I already disassemble this shuttle lever and there is magnetic switches inside, as seen on as that picture. I think the magnet is too weak to connect switches, because i succesfully shift gears using only seperate magnet. I probably need that new shuttle lever or i try DIY fix, glue a new magnet In there... I let you know!

 

[Farmer666]

Now, few months later... If someone have this same problem what i have, problem was a faulty shuttle lever indeed. I bought back then new lever and all problems are stayed gone now over 200hours. And Dyna VT is awesome.