2011-2019 Silverado 2500/3500和Sierra 2500/3500型号可能在卡车后部有颤抖，弹跳或支配条件，同时牵引鹅颈（图2）或5载拖车时制动。制动颤抖动在具有毛额组合重量的车辆上发现通常超过20,000磅。存储与拖车制动系统或电子制动控制模块（EBCM）相关的DTC。
图2
Heavy gooseneck and 5th-wheel trailers have the ability to impose a dynamic pulsing force on the tow vehicle when driving on smooth roads. The pulsing force acts in a forward and reverse direction on the tow vehicle at a rate of 3 to 5 times per second and can be subtle to the driver. As the combination decelerates, the trailer induced pulsing force is still present and, while braking, the driver may unintentionally begin to fluctuate the force on the brake pedal in response to the trailer’s pulsing input force. As the brake pedal force fluctuates, the resulting alternating deceleration forces that the truck produces magnifies the trailer impulse forces, resulting in the shudder condition.
The following tips may help verify the issue and minimize its potential to occur. Trailer, trailer loading, and trailer hitch characteristics will influence the magnitude of a trailer’s pulse force.
Truck and Trailer Weight
测量实际的卡车和拖车重量，其中拖车装载到表现出条件的点。如果超过了任何重量参数，例如前总轴重量额定值（FGAWR），后轴轴重量额定值（RGAWR），总车辆重量额定值（GVWR）或总重量额定值（GCWR），必须在此之前减少负荷进一步调查。
拖车的舌头必须在总拖车总重量的15％到30％的范围内，而不超过卡车后桥毛重重量等级，总车辆重量额定值或总重量额定值。拖车不得超过其重量等级，并且拖车货物必须正确保证。
拴住僵硬
Play and lack of stiffness between the truck and trailer’s hitch components will affect the trailer-induced pulse forces. Gooseneck ball and 5th-wheel kingpin sizes and load ratings must be correct for the trailer weight used. Trailer gooseneck extension set screws must be at the manufacturers specified torque value. Gooseneck ball and coupler parts showing indication of wear should be replaced and 5th-wheel pivot assemblies must be functioning as intended.
Hitch Movement
在加速和减速事件期间观察拖车挂钩和拖车舌。如果注意到过度的运动，则可能需要一个不同的搭配挂钩的挂钩，专注于重量额定值和基础结构。建议使用具有较宽基座的挂钩结构，该结构安装在第5轮挂钩框架上的规定上。还验证已安装挂钩的负载等级。
一级拖车高度
The trailer should be level from front to rear when connected to the truck. (Fig. 3) Height difference between the front and rear of the trailer may contribute to the magnitude of pulsing force the trailer can produce. Trailers that have a tandem axle assembly using a load equalizer beam, as a component in the trailer’s suspension, can produce more pulsing force when the front of the trailer is higher than the rear of trailer. (Fig. 4)
图3.
图4.
拖车能力
The trailer’s tires must be properly inflated and the trailer’s suspension must be functioning as intended. The trailer’s mechanical system performance also should be inspected and any deficiencies corrected.
Trailer Design
Trailers that place cargo closer to ground level, and trailers that have longer distances between the trailer tongue and trailer axles, will reduce the trailer’s forward and reverse pulse forces.
制动应用技术
Stabilizing the driver’s brake apply foot with the heel on the floor while braking will increase the driver’s resistance to unintended fluctuation of the brake pedal in response to trailer pulse forces.
拖车制动评估
当拖车装入展示条件的重量时，验证拖车的制动能力。
与卡车的服务制动器相比，拖车的制动系统应具有相同或更大的能力来停止卡车/拖车组合。From speeds of 20 to 25 mph (32-40 km/h) on level paved roads free from traffic, perform a full manual apply of the trailer brake controller, with the controller set to maximum gain, and no apply of the truck’s service brake. Compare deceleration to the truck’s capability for stopping the combination from the same speed on paved roads during an aggressive brake pedal apply with the brake controller set to minimum gain.
如果拖车制动能力足够，请根据业主手册中的拖车增益调整过程调整制动控制器，并评估卡车和拖车组合再次制动颤抖。
如果拖车制动器不足，拖车或拖车制动器应用系统可能具有电气故障，机械故障，拖车制动器组件或需要修复的拖车轴尺寸不正确。
- 谢谢斯科特菲兰兹
