Profile: Engine & Transmission Exchange deals with remanufacturing & replacement of engines and transmissions. Our products include rottler F65 and sunnen CK-21. Our rottler F65, is a programmable C-N-C boring machine which can bore engines perfectly to exceed OEM tolerances. Sunnen CK-21 is a C-N-C microprocessor-based control system, which allows accurate sizing and boring.