1. Lift the side combo switch handle; the exhaust brake is on while the matching icon appears on the dashboard.
2. Lift the handle again, the exhaust brake is off.
1. There are 4 gears at the right side handle. The initial position is out-of-gear.
2. Turning on the combo switch is for increasing the brake power while the hydrodynamic retarder assists.
3. Even when the hydrodynamic retarder switch on the combo switch is off, the retarder function can turn on automatically when needed as long as the combo switch is on.
Hydrodynamic retarder-brake linkage switch
1. The retarder is off at 0 position; B set is for downhill at constant speed; 1 gear is for 20％or 40％ brake power; 2 gear is for 60％ or 80％.
2. The current speed is set when the retarder is at B position; once the speed reaches the set speed in the downhill, the retarder kicks in.
3. The downhill constant speed function is off when stepping on the pedal; once to release the pedal, the current speed will take as the new set speed.
4. Use the emergency brake if the retarder and the exhaust brake can’t bring enough power downhill.
1. The retarder works best during 40-80km/h.
2. The retarder effect works less when lower than 20km/h.
1. When the retarder coolant liquid temperature is higher than 105℃, it will limit the torque.
2. The ideal engine speed is no lower than 1500rpm/min during the downhill and before the downhill; use the clutch immediately only if to shift the gear.
If not modifying the electric component properly, it might affect the retarder signal to malfunction.
If ABS or EBS takes place, the retarder will drop out immediately.
1. Use the retarder carefully during rainy and snowy weather; it might cause steering failure or rear slippering.
2. Not enough fluid in the transmission might cause retarder failure, brake power loss, or complete down.
3. More details are in the ZF Hydrodynamic Retarder Users Manual.
1. Dismantle the propeller shaft when towing is needed.
2. The low speed data shall not exceed 28km/h, and neutral driving is not allowed.
3. There is low and high speed zone; the middle position is neutral; clutch before gear.
