Sonnax Smart-Tech® Forward Clutch Drum
Transtar Industries & Sonnax
Transtar's community of suppliers represents the most trusted and experienced in the industry. Sonnax shares our vision and meets the premium standards we set for all of our product offerings. We rely on the best aftermarket and OE suppliers in the industry.
For Ford Applications: 4R70E, 4R70W, 4R75E, 4R75W, AODE:
A common failure of listed Ford transmissions is cracking of the forward drum at the snap ring groove. The manufacturing process of the OE snap ring groove creates high-stress points around the circumference of the drum. The drum is active in 1st, 2nd and 3rd gear ranges and suffers the most abuse on a forced 4-3 kick down when it reapplies at higher pressure. (Learn More)
The concurrent pressure from the forward clutch piston combined with the high stress at the snap ring groove causes the upper portion of the drum to split and separate at the groove. Depending on severity of crack, this can result in no forward engagement or slipping in 1st, 2nd and 3rd gear. The forged, one-piece construction of the Sonnax Smart-Tech forward clutch drum (Part #: S76554D) eliminates weakness at these stress points.
Increased groove depth for additional ring support
One-piece forged material provides increased strength and durability over the OE stamped drum.