700R4/4L60E/4L65E Reverse Input Band Drum, New

The reverse input drum, often called the band drum, is the housing the 2-4 band wraps around and the drum that carries the reverse input clutch pack in GM 700R4 and 4L60E-family transmissions. It takes a beating every time the band applies, and the early factory drum is a known cracking point around the band surface and the clutch apply area. When it splits you get reverse slip or no reverse, a burnt band, and sometimes debris that takes out other parts, so most rebuilders replace it as a matter of course rather than reuse a used one.

This is a new drum built to an improved, more durable design than the original early GM casting, so it holds up better than the part it replaces. It fits 700, 700-R4, 4L60, 4L60E, 4L65E and 4L70E automatics and cross-references to the common MD8 and M30 callouts and reference number 99909. Because GM ran early large-feed-hole and later variations over this transmission family, confirm your drum style against the unit you are building before installing.

On the bench it is a straightforward swap during a rebuild: move your reverse input sprag, clutches and the input shaft into the new drum, set your clutch clearance, and install it with a fresh 2-4 band. Ships from the USA; handling in 1-2 business days.