Abstract: A clutch pedal operated rod to the brake lever in a transmission brake system for tractors and the like is formed of two spaced longitudinally aligned rod lengths connected by a coupling for transmitting force therebetween through a fluid medium. The coupling is secured to the end of one length and slidable receives a spring loaded piston head on the aligned end of the other length. The piston head is in fluid seal engagement with the coupling and separates such coupling into an upper and lower chamber with a fluid supply disposed in the upper chamber in non-operating position. A fluid conduit exteriorly of the coupling communicates with both chambers. Depression of the clutch pedal effects relative movement of the piston head against the fluid supply in the upper chamber where the fluid acts as a solid member under pressure to transmit force to the brake operating rod for stopping the transmission.