Ford CD4E Mazda LA4AEL Transmission Oversized Regulator and Bypass Kit 73840-MK Symptoms: Bushing failure Code 28, 1744, 1740 Cracked drum High line pressure Loss of lube oil No cooler flow during failsafe Planetary failure Cause: Worn casting bores at the pressure regulator and converter regulator valves, and insufficient cooler and converter flow. Correction: The oversized PR valve restores the balance circuit to correct high line pressure and guards against excess EPC/TV pressure. The PR valve and converter regulator valve have modifications to properly regulate converter and cooler flow. 73840-RK Oversized Pressure Regulator & Converter Regulator Valve Kit 73840-BK Oversized Bypass Clutch Control Valve Kit The CD4E transmission frequently exhibits such symptoms as lube failure, harsh shifts and line pressure instability as well as a variety of TCC Lockup issues. Sonnax master kit 73840-MK contains both the Regulator Kit 73840-RK and the Bypass Kit 73840-BK to address issues in both areas. See the individual kits for more detail. Both the Regulator and Bypass Kits require reaming for installation. Tool Kit required and not included if you need the tool kit please let us know they are available (Part # F-73840-TL)