There is a reverse drum in the AOD, and it uses a one-way ratcheting device-or sprag-to engage reverse. The stock sprag is a lightweight, pressed-steel and plastic-bushing birdcage containing some delicate rollers and ratchets. It's seen here standing up in the heavier race it runs inside of. In the background is the heavy-duty "dial sprag" CPT uses. It uses a much heavier spring-loaded ratchet that gives off a satisfying "clack, clack, clack" when rotated. Compared to the stocker, it's bombproof. Not showing is the reverse drum, which uses beefy dog-teeth lugs to engage the dial sprag, rather than the undulating ramps of the stocker-altogether worlds stronger than stock.