September 19, 2019
The 3-5-R waved plate in GM Gen. 1 and 2 6T70, 6T75 units commonly fails and breaks into pieces, resulting in code P0776, harsh and flare shifts or complete loss of 3-5-R. While the OEM attempted to prevent this problem by issuing an updated (shot-peened) plate, it continues to fail in some units, damaging the drum housing splines. The teeth on the OE plate are high-stress points that cannot stand up to long-term fatigue. Even plates that haven’t broken can have micro-fractures at the tooth corners and be on the verge of failure.
Sonnax 3-5-R drum saver kit 124555K is an effective and affordable way to guard against failures and costly comebacks. The improved Sonnax waved plate is shot-peened like the updated OE plate, but is designed with no teeth to eliminate virtually all stress points. When positioned on the drum with the custom, cupped steel plate, this guarantees the best protection against plate and drum failure.
The drum saver kit also can be used to salvage a damaged drum — saving you the hassle and expense of assembling a new one. With no teeth to hang up on damaged drum splines, the Sonnax waved plate can ride in this area without hanging up or interfering with proper clutch pack travel.