4L60E Reverse Input Clutch Housing Drum 24245624

This is the GM Genuine Parts reverse input clutch housing, OE part number 24245624, for the 700R4 / 4L60 / 4L60E / 4L65E / 4L70E family used from 1987 through 2014. It is the drum that carries the reverse input clutch pack and its apply piston, and the machined outer surface is what the 2-4 band wraps. That makes it one of the few parts in the unit doing two jobs at once, which is why it wears out faster than most people expect.

You replace this housing when the outer band surface is scored, blued, or worn into a step. A 2-4 band that has been slipping polishes and grooves that surface, and once it is grooved a new band will not hold - you get the same 2-3 slip and burnt band smell a few hundred miles after the rebuild. The other reasons to swap it are a cracked drum, a burnt reverse input clutch pack that has scorched the splines, or a piston bore that is scuffed and will not hold a seal. Bench check: set the drum on a flat surface, run a fingernail across the band area, and if you can feel a ridge, do not reuse it.

On the bench this housing goes in with new lip seals on the reverse input piston, then the reverse input clutch pack (frictions and steels come from your rebuild kit, not with this housing). Set the clutch clearance with the selective apply plate before you build it into the case, then air check the reverse input circuit at the case feed hole - you want a solid thump, not a hiss. Soak new frictions in ATF first. When you drop the drum over the input housing, make sure the internal splines line up all the way down or the endplay reading will be wrong and the sun gear shell will take the abuse later.

This is the OE housing itself with the piston, not a full clutch assembly. Order it alongside a 4L60E master rebuild kit, a new 2-4 band, and a hardened reaction sun shell if the unit came apart from a hard 2-3 failure - those parts almost always go together on this transmission.