TM gear box fault

[YELROM]

We have a New Holland TM155 power command that will only drive in first gear.
It is in the field and i have not been to look at it but the lad says that no matter what gear you put it in it flashes CP for clutch pedal then when you press the clutch it changes down to first gear

Anyone any ideas what might be wrong

@cosmagedon would you have any idea?

 

[Aftermaths]

On the right hand side, behind the bank of solenoids, you can find a pair of potentiometers that work out where everything is so it can change gear, take these off and polish up the brass where the bolt goes through (they earth through here) and also the tractor side, this usually cures any oddball tm gearbox faults. There is also a pair of sensors down there which also get bad earth's and cause issues. Usually works for me anyway

 

[YELROM]

On the right hand side, behind the bank of solenoids, you can find a pair of potentiometers that work out where everything is so it can change gear, take these off and polish up the brass where the bolt goes through (they earth through here) and also the tractor side, this usually cures any oddball tm gearbox faults. There is also a pair of sensors down there which also get bad earth's and cause issues. Usually works for me anyway

Thanks I’ll try that

 

[horace]

There are no potentiometers on the RHS of a power command. And even if there were they definitely don't earth through the brass bushes. They are only there to prevent over torquing.
All your gearbox solenoids are under the inspection cover in the cab. Floor mat out, cover out.
I would be checking the wiring on those. Take the LHS cover off the dash by the clutch pedal. Check the wiring on the pedal potentiometer and the disconnect switch.
Check the wiring to the 3 speed sensors going into the RHS of the box. From the outside they will be mounted the same way as the damper plate sensor on the bell housing.
Are there any error codes at all?

 

[Lincsman]

Can you set off in 1st gear then change up?.. the default start should be 6th IIRC

 

[cosmagedon]

We have a New Holland TM155 power command that will only drive in first gear.
It is in the field and i have not been to look at it but the lad says that no matter what gear you put it in it flashes CP for clutch pedal then when you press the clutch it changes down to first gear

Anyone any ideas what might be wrong

@cosmagedon would you have any idea?

First thing is to try and calibrate it, if there's a fault it will usually bring it up as a U code.

 

[YELROM]

First thing is to try and calibrate it, if there's a fault it will usually bring it up as a U code.

I will try calibrating it as I went to it today and it’s working as normal

 

[cosmagedon]

I will try calibrating it as I went to it today and it’s working as normal

The best type of fault

Check the flywheel speed sensor when you get a chance, make sure it's not damaged inside by the damper plate breaking up.

 

[YELROM]

The tractor was playing up again the other day so I calibrated the gearbox and it brought up error code FA2 which is medium range clutch solenoid open circuit or shot to ground, so I have got a new solenoid, are they on top of the gearbox under the floor and I assume if it’s the medium range one it will be the middle one of three @cosmagedon

 

[Bumble Bee]

The tractor was playing up again the other day so I calibrated the gearbox and it brought up error code FA2 which is medium range clutch solenoid open circuit or shot to ground, so I have got a new solenoid, are they on top of the gearbox under the floor and I assume if it’s the medium range one it will be the middle one of three @cosmagedon

I'm pretty sure that the casting where the solenoid screws into the top casing 'M' cast into it. Along with 'L' 'R' etc.

 

[cosmagedon]

As above, take the floor out and on top of the gearbox you will see all the solenoids.

 

[ridger]

The tractor was playing up again the other day so I calibrated the gearbox and it brought up error code FA2 which is medium range clutch solenoid open circuit or shot to ground, so I have got a new solenoid, are they on top of the gearbox under the floor and I assume if it’s the medium range one it will be the middle one of three @cosmagedon

Mine done similar but there was a picture of a snail on gear screen, it was convinced in was in creeper gear