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Trembling GT500

Hi I’m writing this on behalf of my buddy in England who has a Shelby Mustang GT500 registered in 2006 (2007/08 model). It has a manual Tremec gearbox. Whenever he holds the biting point he gets a ‘hissing’ sound and 9 times out of 10 when driven away in 1st gear from standing-still he gets considerable ‘judder’ from the engine-however if the car is already in motion, no matter how slow, it doesn’t do it. He has had a new clutch, flywheel and thrust bearing fitted but within a few days the hissing and judder were back and gear changes are not smooth anymore. The UK dealership has said there is nothing more they can do. Any advice would be appreciated. Thank you.

Are these 1st gear starts from a standstill “Normal driving” or are we talking full throttle hole shots??

"Whenever he holds the biting point " What exactly does that mean?? Intentionally slipping the clutch to avoid breaking the tires loose?

This vehicle uses a ceramic dual disc clutch… The ceramic lining will make a hissing noise as it slips and then engages… Normal operation characteristic for a clutch of this type.

Becareful, these clutches do not take kindly to riding the clutch or letting it slip. The discs are small and will build heat very quickly (especially when riding or when trying to engage very softly) In cases where too much heat is generated the plates will distort and will look like bellville springs or tapered washers… When this occurs the clutch will no longer disengage properly and shifting will be very difficult if not impossible at idle when the vehicle is stopped.

Experience has shown that this will occur for three different reasons… one… Poor operator clutch habits. Two, improper input shaft grease application. Three, improper surface finish on the transmission input shaft. There was a technical service bulletin for issue number three…

TSB applicable to concern is…10-3-8… There is also a PCM reprogram involved in this TSB… Again this clutch is very digital… It is happier either fully disengaged or fully engaged… Too much in between makes it a very unhappy. So when it is time to get the vehicle moving, let the clutch go, the faster the better.