Join Date: Jun 2007
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4L80E shudders/grabs when downshifting out of OD
My truck shifts and runs great. However the 4L80E shudders/grabs when downshifting out of OD. It feels worse when towing. If you floor it to throttle shift it it's much better (maybe not perfect), but if you're light on throttle and it shifts itself, it really grabs. Scary sensation (noise and hesitation). I've had the valve body bored/rebuilt previous to this problem and all was well. Seems to have come into play after engine swap and isn't going away. To me it feels like the torque convertor doesn't unlock quick enough before downshift. Any ideas before tranny shop?