Fits '06-earlier reaction shafts only. Requires use of OE bearing 8642191 or 24217327 (not included in kit). See instructions for details.
The steepest first gear ratio of any four-speed automatic (3.06) belongs to the GM 4L60 (700-R4)/4L60-E family of transmissions. The shift from 3.06 ratio (1st gear) to 1.63 ratio (2nd gear) is a dramatic RPM drop that causes performance engines to fall out of their power band.
Sonnax 2.84 input carrier kit 77284-K transforms the popular 4L60 series from an OE “wide ratio” 3.06/1.63 to a “close ratio” 2.84/1.55 for game-changing acceleration on the track. This keeps performance engines in the optimal power band while allowing a longer pull in first and second gears, improving consistency and performance.
Manufactured and engineered for outstanding durability, the carrier's gears are precision-ground to OE standards, thrust washers feature highly wear-resistant PTFE-coated material and the captured bearing is thicker late design. Lube channels direct oil to the pinion pins, and the carrier can be disassembled for inspection and service.
February 22, 2016
April 28, 2017