How to activate the hydraulics for Dump Body on T series?

[RedTailBullet]

I goes through all the controls and assigned all vehicle specific controls but the hydraulics doesn't seems to work.

[Nadeox1]

If you have any mods for the T-Series, disable them and reset your bindings.
A conflicting mod could prevent that part from working correctly.

[Tmccanna]

the bind should be the discharg shute key