4L70E Input Drum 2005, remanufactured and ready to install. Fits the 4L70E. Ships fast from the USA.
A 4L70E Silverado, Sierra, Tahoe, Yukon or Trailblazer SS that slips into overdrive, flares on the 2-3 shift, or leaves friction material in the pan has usually burned the 3-4 clutch inside the input drum. This listing is a loaded, remanufactured GM input drum for 2005-and-later 4L60E, 4L65E and 4L70E units, GM part number 8678716. It comes with the 30-spline input shaft pressed in, carrying the reluctor for the input speed sensor and sized for a 300mm converter. The drum is built with new pistons, new high-performance clutches and remanufactured steels, and each one is tested before it ships. You are buying a finished assembly, not a bare housing to fill with parts.
The input drum, also called the input housing, is splined to the turbine through the input shaft, so it turns whenever the converter turns. It holds three clutch packs: the forward clutch, the overrun clutch and the 3-4 clutch. Pistons inside the drum apply those packs with oil fed through sealing rings on the shaft. The 3-4 pack stays applied through 3rd and overdrive, so on a heavy truck it carries engine torque for most of the miles. Sonnax names the limits of the factory input housing as the root cause of 3-4 burnup in hard-working units.
Input shafts in this family are not all alike. Sonnax lists separate shafts for 300mm-converter units with and without a reluctor, which tells you the drum must match both your converter size and whether your transmission reads input speed. The 4L70E uses an input speed sensor, and Transmission Digest documents P0716 and P0717 input speed codes on this unit. A drum without the reluctor, or with a shaft for a smaller converter, will not work in a unit built for this one.
Find out why the old drum failed. Sonnax traces most burnt 3-4 clutches to low line pressure or a 3rd-gear oil leak, including a leaking 3rd accumulator checkball capsule and a worn input housing checkball that should hold 25 in-Hg of vacuum. Our 4L70E 3-4 clutch failure guide walks through those checks, and the common problems guide covers the speed sensor and harness faults that can mimic slipping.
The listing covers 2005-and-later 4L60E, 4L65E and 4L70E transmissions with a 300mm converter and reluctor-style input shaft. Count the splines on your old shaft, check for the reluctor ring, and confirm your converter size before ordering, or send us your year and VIN. The 4L65E vs 4L70E guide helps identify which unit you have, and every part we carry for it is in the 4L70E parts collection.
If the unit is apart, a 2004-2014 master rebuild kit covers the seals and gaskets for the rest of the transmission. If the drum burned from low pressure, fix the cause first or the new clutches will follow the old ones.
| Fits | 4L70E 2005 |
| Part type | Input Drum |
| Condition | Remanufactured |
| Brand | OEM |
| 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 loaded. The listing includes the drum, input shaft with reluctor, new pistons, new clutches and remanufactured steels, tested before shipping.
The listing covers 2005-and-later 4L60E, 4L65E and 4L70E units with a 300mm converter and reluctor-style 30-spline input shaft. Match those details to your old drum.
It is the toothed ring the input speed sensor reads. Units with an input speed sensor need it, or the computer sets input speed codes such as P0716 or P0717.
Most 3-4 clutch failures come from low line pressure or a 3rd-gear oil leak, such as a leaking accumulator checkball capsule or worn sealing rings. Find and fix that before installing this drum.
GM specifies Dexron VI. Soak any loose new frictions before assembly and fill with fresh Dexron VI after the rebuild.
