4L70E Input Drum 1987, remanufactured and ready to install. Fits the 4L70E. Ships fast from the USA.
If you are tearing down a GM rear-drive four-speed and the drum under the 2-4 band is blued, grooved or will not hold air in Reverse, this is the part you are shopping for. This remanufactured input drum is listed for 1987 and carries GM reference 24245624, the number GM catalogs as the reverse input clutch housing assembly. It is offered for 4L70E work and also suits older family members going back to the 1987 700-R4, so it fits both a truck being restored and a Silverado, Tahoe or Trailblazer SS unit getting overhauled. It ships from the USA with a 1-year warranty.
GM did not use the 4L70E name in 1987. That year the unit was the hydraulic 700-R4, and the 4L70E label arrived decades later on the heavy-duty version used in 2006-2013 Silverado, Sierra, Tahoe, Yukon and Trailblazer SS models. What ties them together is the reverse input housing: GM's current 24245624 supersedes earlier numbers 8642905, 8681295 and 24241494, so one service housing covers a long run of the family. Our 4L60E, 4L65E and 4L70E interchange guide lays out which hard parts cross between the three and which do not.
Rebuilders call it the input drum or reverse input drum, and GM calls it the reverse input clutch housing. It sits directly behind the pump. Its ground outer face is the friction surface for the 2-4 band: when the servo strokes, the band clamps the drum, the drum's drive tabs hold the reaction sun shell, and you get 2nd and 4th. Inside the drum is the reverse input clutch pack and piston, which turn that same sun shell when the shifter is in Reverse. The listing photo for this 1987 unit shows the housing with a clutch pack already fitted, the tabbed open end and the bronze bushing in the hub.
Sonnax lists burnt Reverse clutch, overheated 2-4 band, reduced 2-4 band life and Reverse chatter among catalogued 4L70E complaints, and every one of them can involve this housing.
A drum rarely fails on its own. Low line pressure, a leaking servo, a bad band apply pin length or a sticking valve all overheat the band and the reverse clutch, and a new drum will not survive the same cause. Run the checks in our 4L70E delayed engagement guide if Reverse is late, and see the 4L70E common problems guide for the pressure faults behind band burn. On the bench, lay a straightedge across the band surface: Sonnax notes that a used band compresses the drum and leaves a shallow dish that causes 2nd gear slip and glazing. Then air-check the reverse piston and check the bushing against the pump hub.
The listing is for 1987 with reference 24245624. Because the family had running changes in bushings and related parts over its life, compare your old housing's tab count, bushing size and overall height with this one, or send us the year and VIN and we will confirm it before shipping. If you want a housing listed for the full 1987-2014 span, see the 4L70E input drum 1987-2014. Everything else for this unit is in the 4L70E parts collection.
| Fits | 4L70E 1987 |
| Part type | Input Drum |
| Condition | Remanufactured |
| Brand | GM |
| Reference | 24245624 |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is GM's reverse input clutch housing assembly for this transmission family. It replaces earlier numbers 8642905, 8681295 and 24241494, which is why one housing is offered for both older 700-R4 work and 4L70E builds.
No. In 1987 the unit was the 700-R4. The 4L70E name came on 2006 and later heavy-duty applications, but the reverse input housing carries across the family.
The listing photo shows a clutch pack fitted. Disassemble and inspect it, and replace the frictions and piston seals if you are not certain of their condition.
Yes. A used band has worn to the shape of the old drum and will not seat on a refinished one, which leads to 2nd and 4th gear slip.
Only if the reverse input clutch or the housing is at fault. Low pressure in Reverse, a valve body problem or the low-reverse clutch can also cause it, so diagnose first.
Dexron VI ATF, the fluid GM lists for 4L70E vehicles and the replacement for earlier Dexron fluids.
