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Old 09-18-2017, 08:53 PM
Dick Boneske's Avatar
Dick Boneske Dick Boneske is offline
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Default Car Shudders When Stopping--2008 GP GXP V8

My GXP that I just bought shudders when stopping. At about 20 mph, the car shudders as though the transmission isn't shifting down--similar to the old Roto-Hydramatics when the linkage wasn't set right.

The problem goes away if I shift to neutral before stopping or if I enter the Slapshift mode so the car is in first gear when stopping.

Does anyone have suggestions on a fix--vacuum modulator, adjustment, etc.?

'64 GTO Tripower Hardtop (Wife's Car)
'64 GTO Tripower Post Coupe (My Car)
'08 Grand Prix GXP LS4 V8 (Wife's Car)
'09 Pontiac G8 GT 6.0 V8
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Old 09-20-2017, 05:09 AM
Geoff Geoff is offline
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This was a common problem on some Mitsubishi cars when l/u converters were first used. The fix was to use ONLY Mitsu trans fluid in the trans.
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Old 09-20-2017, 08:34 AM
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ponchjoe ponchjoe is offline
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TCC engage/disengage issue? Any codes present? Take it to someone that can plug in the scan tool and watch the switches in the trans, I'll bet it would be easy to see.
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