Ford AODE 4R70W 4R75W Transmission Oversized Regulator & Boost Valve Kit Symptoms: Band failure Clutch failure Damaged case Delayed Reverse Erratic Reverse pressure Low line rise Soft shifts Throttle buzz Uncontrolled pressure in Reverse Cause: Wear at the pressure regulator valve bore and reverse boost sleeve allows valuable EPC, line pressure and reverse boost to exhaust. Correction: The Sonnax kit includes an oversized pressure regulator valve to restore correct clearances for proper hydraulic control, and a replacement reverse boost valve assembly. '96 -later A common complaint in vehicles with AODE and 4R70W transmissions is low line pressure or throttle-sensitive buzz, especially when hot. This wear allows EPC (electronic pressure control) oil to leak to exhaust, resulting in poor line rise. When the oil temperature increases, the oil becomes less viscous and more leakage occurs. Sonnax offers standard size valves 76948-01 ('91-'95) and 76948-09 ('96-later). However, when valve bodies are severely worn, a standard size replacement valve will still allow leakage. Sonnax also offers 76948-16K and 76948-17K, two oversized pressure regulator valves that allow the valve body to be salvaged. Improved PR/EPC reaction area ratio provides higher line rise response to EPC pressure, which results in noticeably firmer shifts. Oversized pressure regulator valves are manufactured from hard-anodized aluminum to prevent wear. PR valves have annular grooves to prevent side loading that results in wear. The spring seat on the PR valves has been lengthened to compensate for the increased diameter. Anodized aluminum boost valve is slightly larger than OE, to provide to correct ratio with the oversized pressure regulator valve. Either tool kit works for all model years.