ive had a rebuilt from Preston Automotives ive got a 4 speed xr6t since the rebuilt ive done areound 3000km's and have been there twicw so they can put an additive in the gearbox.. my problem is that on a 1/4 acceration I can hear a clunk noise and its coming from the tailshaft to where it meets the diff everytime it changes gears I hear the f*cking cluck, not a donk noise I know the donk noise is from the harder shifts, but this is a clunkand its driving me mad,, does any1 know of this problem or has it or has gotton it fixed please help me as this is driving me mad, makes me not wonna drive the f*cking car, im going to call preston and tell them about it as I have last month and they said lets put a double dosage of addative in the gear box it should fix it... but know it hasnt so yeahhhh please guys help me