Jeep Front Truss Rock Krawler Upper Control Arm Mount Driver Side Jeep XJ/TJ/LJ/MJ TNT Customs TNT Customs. If you have a Rock Krawler rand suspension, this upper mount is for you. It's specially designed to work with Rock Krawler's arms. This truss upper control arm mount comes attached to your truss when ordered with the truss. Made of 3/16th steel, this mount gives you added strength for your upper control arm to mount to the front truss. Bushings and sleeve are included with the mount.