Ford learned through grueling competition that the Borg-Warner T-10 four-speed transmission ... Courtesy David Kee Toploader Transmissions. Top Loader bellhousings must measure 6 1/4-inches ...

Ford's "RUG" top loader 4-speed has been around in one form or another since 1964. Up until its first phase out in 1973, it was built as a "conventional" transmission with 1:1 final drive ratio.

Born of this quest to win was the top-loading Ford Design four-speed transmission. Obviously, the Top Loader or Toploader gets its name from its top-loading main case that offers unmatched durability.