OD servo reg. boostvalve 4R70W, AODE

OD servo reg. boostvalve 4R70W, AODE Valve Sleeve Common problems with a 4R70W are a burned overdrive band, loss of 4th gear, and/or a 4-3-neutral shift pattern. These problems can be caused by wear at the inside diameter of the overdrive servo regulator boost valve sleeve, due to constant oscillation. Excessive wear allows valuable overdrive oil to leak, preventing the proper regulation of the overdrive servo. The Sonnax replacement assembly maintains critical tolerances that re-establish the hydraulic integrity of the circuit. Hard-coat anodized valve and high-grade aluminum sleeve resist wear. Closely toleranced sleeve improves sealing. Symptoms: 4-3 Neutral Burnt OD band No 4th Cause: Wear at the inside diameter of the overdrive servo regulator boost valve sleeve due to constant oscillation allows valuable overdrive oil to leak. Correction: The Sonnax replacement assembly provides better sealing at all temperature ranges.