The factory Jeep TJ frame is designed around the original rear axle location. It uses a raised section over the axle to allow upward suspension travel, then drops down behind the axle toward the rear bumper. This works in a stock configuration, but it becomes a problem once the rear axle is moved to stretch the wheelbase.
When the axle is relocated rearward, it is no longer positioned under the raised portion of the frame. Instead, it sits under the lower section of the frame rails. In this position, the axle will contact the frame during compression, limiting up travel and preventing the suspension from working correctly.
The Motobilt TJ Back Half Kit replaces the rear section of the frame to correct this geometry. Instead of dropping down behind the axle, the new frame rails stay high and consistent from the axle rearward all the way to the rear bumper.
This allows the rear axle to be moved backward to stretch the wheelbase while still maintaining proper suspension up travel without increasing ride height. The result is a more stable chassis with better suspension performance and improved capability on the trail.
In addition to correcting the frame geometry, the kit narrows and repositions the frame rails under the rear floor. This creates the space needed for coilovers, bypass shocks, or ORI struts while improving departure angle and rear ground clearance.
The integrated rear bumper is positioned higher and includes 3/4 inch thick d-ring mounts for recovery. The overall structure provides a cleaner and more functional layout for building a properly packaged rear suspension system.
This is not a factory frame repair. It is a rear chassis system designed for advanced builds where suspension layout, wheelbase, and frame geometry all need to be corrected together.
Like all Motobilt components, this kit was designed by builders who understand frame limitations, suspension movement, and real off-road use.
