4L60E GM Mock Up Transmission Our patent-pending tab-and-slot version of the Swap Block ® Mock Up transmission block provides accurate transmission mounting and yoke positions. This unique design is lightweight and comes disassembled for ease of shipping and storage. One tool accomplishes accurate placement of a newer style 4l60e transmission found in GM cars and trucks from 1996-2014 with removable bellhousing. Easily positioned by hand, there is no need to bench-press a heavy transmission into place for fitment and fabrication of crossmember, etc. Save time and money and work more safely.