Brand Name:
for Ford
Model Number:
4R70W;4R75
Typical Faults:
One-Way Clutch Roller Jamming
Symptom: Harsh 1-2 upshift or delayed reverse engagement (P0730/P0756 codes)
Cause: Contaminated fluid or sprag spring fatigue
Drum Spline Wear
Symptom: Reverse slippage or metallic noise
Trigger: Hard shifts causing torsional stress
Thrust Washer Failure
Symptom: Axial play >0.25mm (whining in reverse)
Root Cause: Improper assembly torque
Critical Checks:
Sprag Clutch Test: Should lock counterclockwise only
Drum Runout: <0.08mm tolerance
Fluid: MERCON V only – others degrade OWC lubrication
Pro Tip: Replace entire drum assembly if splines show polishing – indicates mutual wear with planetary gears.
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