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dation and varnish buildup which interferes with CAUSES OF BURNT FLUID Burnt, discolored fluid is a result of overheating which has two primary causes. (1) A result of restricted fluid flow through the main and/or auxiliary cooler. This condition is usu- (2) Heavy duty operation with a vehicle not prop- erly equipped for this type of operation. Trailer tow- fluid if the vehicle is improperly equipped. Such vehicles should have an auxiliary FLUID CONTAMINATION Transmission fluid contamination is generally a result of: • adding incorrect fluid • failure to clean dipstick and fill tube when checking level • engine coolant entering the fluid • internal failure that generates debris • overheat that generates sludge (fluid break- down) • failure to reverse flush cooler and lines after repair • failure to replace contaminated converter after repair The use of non recommended fluids can result in transmission failure. The usual results are erratic The dipstick cap and fill tube should be wiped clean before checking fluid level. Dirt, grease and Engine coolant in the transmission fluid is gener- ally caused by a cooler malfunction. The only remedy The transmission cooler and lines should be reverse flushed whenever a malfunction generates Failure to flush the cooler and lines will result in recontamination. Flushing applies to auxiliary cool- 45RFE AUTOMATIC TRANSMISSION GENERAL CAUTION: Before attempting any repair on a 45RFE Transmission malfunctions may be caused by these general conditions: • Poor engine performance • Improper adjustments • Hydraulic malfunctions • Mechanical malfunctions • Electronic malfunctions by checking the easily accessible variables: fluid level PRELIMINARY DIAGNOSIS Two basic procedures are required. One procedure for vehicles that are drivable and an alternate proce- VEHICLE IS DRIVABLE (1) Check for transmission fault codes using DRB scan tool. (2) Check fluid level and condition. on delayed, erratic, or harsh shifts. (4) Road test and note how transmission upshifts, downshifts, and engages. (5) Perform stall test if complaint is based on slug- gish acceleration. Or, if abnormal throttle opening is (6) Perform hydraulic pressure test if shift prob- lems were noted during road test. 21 - 206 45RFE AUTOMATIC TRANSMISSION WJ DIAGNOSIS AND TESTING (Continued) |