CAT 924 G problems with the gearbox

Hello,

maybe someone can help me here. I bought a 924 G Cat for our farm over here and I noticed that the machine only changes speed on the road (manually 1 to 4, not automatically), when the AUTOSHIFT button is pressed. If the Autoshift button is not pressed, the machine goes very slow in all 4 gears, maybe 10 kmh. What could be wrong with the transmission? I also work with the autoshift button pressed in first or second gear.

Thanks for help!

Gerry
Bellow a button pad of my machine:

Attached Images