Back Half Frame Kit for Jeep JK/JKU

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This cutting edge design is the first of its kind for the Jeep JK. The kit replaces the entire back half of the frame from below the doors to the rear bumper. The Motobilt Jeep JK back half kit was 3 D cad designed by our legendary team of experts. The three main factors considered in the design were room for coil over shocks, a rear mounted fuel cell, and the ability to mount a true 4 link suspension.

The kit includes:

  • Passenger side frame rails. 2 pcs
  • Driver side frame rails. 2 pcs
  • Frame rail connecting plates 2 pcs
  • Rear cross member 1 pcs
  • Frame chop rear bumper 1 pcs


  • Works with both the 2 door JK or the 4 door JKU
  • Frame rails above axle center line are moved inwards 5 inches per side allowing room for coil overs.
  • Room for single or dual shocks.
  • Main frame rails include 2 new body mounts that are matched to the OEM specifications for precision.
  • Two of the factory body mounts over the axle are removed.
  • 4 frame cross members are removed allowing room for more axle travel upward. This allows a lower center of gravity.
  • The new 3/16 inch thick steel frame rails provide a much stronger mounting point for link mounts then the thin weak factory frame rails.
  • An optional cross member to mount 4 link mounts will be available soon.
  • An optional aluminum fuel cell with 3/16 inch thick steel plate skid plate will be available soon. An OEM sending unit will be compatible with the new cell.
  • Precise easy to locate points for cutting the factory frame rails are provided and alignment holes are in place to make the install fool proof.
  • The install requires the frame to be cut with a saw and not a torch. This makes for a clean, quick, and precise install.
  • The rear frame rails are shortened 2.5 inches over stock and moved up 1 1/8 inches.
  • Will work with Antirock sway bar kit for JK
  • Weight: 166lbs (approx.)


  • Your stock exhaust will have to be modified
  • Requires cutting and welding
  • Must remove factory fuel cell.
  • Aftermarket fuel cell required.

Product Components


Installation Instructions