[99cobralover]

hey guys, just checked back. the "clunk" is at the rear of car when i shift gears or let on the gas or let off the gas. the car has 110,000 miles and i was told the prev. driver rode the car hard. (i gave 4000 for a 99 conv. cobra. i'm not bitching) but, i would like to follow up on any suggestions for diagnosing this noise. there is about a 3/4 inch back and forth movement of the drive shaft at the rear diff.if i lock the emergancy brake. any suggestions? anybody covered a shimming of the rear end to tighten it up.or maybe a cost of a rebuild. thanks

[2oo5GT]

most mustangs do have a play that is normal. like slowing down and then give it a little gas and you hear a clunk and sounds like what you have mentioned. I think all my mustangs have done that.
Unless it's a loud metal on metal bang or something.

[bkaul]

There was a TSB about drivetrain clunk back in '01 ... had to do with retorquing all the mounting bolts for the IRS. Doing that can help some. I had this in my '01 Cobra until it got rear-ended ... when the dealer's body shop had to remove & reinstall the suspension to replace the trunk floorpan, they managed to fix the problem as a side effect; I imagine just by putting it back together tighter than it had been from the factory.

The play in the driveline is normal and nothing to worry about. The audible clunk can often be drastically reduced by tightening up the bolts/bushings on the IRS mounts though.