Before attempting any repair on the 42RLE Four Speed Automatic Transmission, always check for proper shift cable adjustment. Also check for diagnostic trouble codes with the DRB® scan tool and the 42RLE Transmission Diagnostic Procedure Manual.42RLE automatic transmission malfunctions may be caused by these general conditions:Poor engine performanceImproper adjustmentsHydraulic malfunctionsMechanical malfunctionsElectronic malfunctionsWhen diagnosing a problem always begin with recording the complaint. The complaint should be defined as specific as possible. Include the following checks:Temperature at occurrence (cold, hot, both)Dynamic conditions (acceleration, deceleration, upshift, cornering)Elements in use when condition occurs (what gear is transmission in during condition)Road and weather conditionsAny other useful diagnostic information.After noting all conditions, check the easily accessible variables:Fluid level and conditionShift cable adjustmentDiagnostic trouble code inspectionThen perform a road test to determine if the problem has been corrected or that more diagnosis is necessary. If the problem exists after the preliminary tests and corrections are completed, hydraulic pressure checks should be performed.