COMPLAINT: Converter clutch shudder
CAUSE: One cause can be low converter regulator charge pressure, Figure 1, Another cause can be slow drain of converter oil in front of clutch piston,
CORRECTION Install stronger regulator valve spring 8637887 or use a spring from a THM 400 forward or direct clutch retainer Figure 2. Drill converter exhaust hole in separator plate to .080”.
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THM 4L60 (700-R4) HARSH DOWNSHIFT CLUNK IN D3 ONLY
COMPLAINT: Harsh downshift clunk with selector in D3 only.
CAUSE: The cause could be the 2nd apply piston.
CORRECTION: Modify the 2nd apply piston by machining the inner hub and remove .125″ (See Figure 3).