Sounds like a clutch to me. If you shift and it takes a few seconds to completely engage, that is a slipping clutch. Change it ASAP. Mine had been slipping for a few months when I changed mine, and entire disc was smooth.....probably didn't have much life left on it.
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2015 Ford Mustang GT Fastback - Ingot Silver - 6M - Performance Package - Gibson Catback, JLT CAI, FR 47lb injectors, BAMA E85 tune, Eibach Sportline, BMR wheel hop kit, UPR oil separator, Steeda shifter bushing/bracket
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