• No Forward
  • Slipping gears
  • Broken clutch drum
  • Ratio codes


OE forward clutch drum splits at snap ring groove due to manufacturing process, creating no or slipping forward clutch apply.


Restore proper gear engagement and hold by installing sturdier, forged Sonnax forward clutch drum.

4R70E, 4R70W, 4R75E, 4R75W, AODE

Smart-Tech® Forward Clutch Drum
Part No. 76654-01K

Compatible with ISS-equipped and non ISS-equipped applications

View Instructions Find a Distributor

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.

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 76654-01K 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

I have used this in a 600whp supercharged Mercury Marauder along with other Sonnax parts, and man did the customer love what we did. You guys are the masterminds of this industry.

J. Johnson
Crystal Lake Transmissions

March 07, 2014

Transmission Report: Top Repair Solutions for All Rebuild Levels

Topics: Rebuilding Tips Diagnostics And Theory Transmission Report Newsletters Transmission Toyota/Lexus Chrysler A340E Transmission A340F Transmission 48RE Transmission 46RH Transmission 47RH Transmission 46RE Transmission 47RE Transmission

Read Now

May 26, 2015

Transmission Report: Learn LIVE with Sonnax!

Topics: Diagnostics And Theory Transmission Report Newsletters Valve Body Reaming Transmission Ford 5R110W Transmission 6R140 Transmission

Read Now

March 09, 2016

Transmission Report: U341E/F TCC Slip Diagnosis

Topics: Transmission Report Newsletters Transmission Toyota/Lexus U341F Transmission U341E Transmission

Read Now

May 22, 2015

Stop 4R70W Forward Drum Failure with a Sonnax Smart-Tech® Drum

Topics: Diagnostics And Theory Transmission Ford 4R75W Transmission 4R70W Transmission 4R70E Transmission 4R75E Transmission

Watch Now

September 30, 2005

Anatomy of a Transmission: Oil Flow in the Pump-PR-Converter-Cooler Lube Circuits

Gregg Nader

Topics: Diagnostics And Theory Transmission

Read Now

  • 76654 01k
  • 76654 01k details