My '74 2.0 developed an un ungodly sound; thought my engine was shot. Sounded like everything was falling apart when revving it and I was imagining the worse. Then I realized I was hearing the same sound as I drove over bumps. Getting underneath I found I could duplicate the sound by pushing upward on the muffler. Low and behold, the two large nuts that fasten the angled muffler bracket to the rear of the tranny had backed off, allowing things to vibrate like crazy. Looks like the P.O. had forgot to install lock nuts. Refastened it all properly and all is quiet again. Needles to say I am very relieved.

Ansbacher

Glad to hear it was that simple/minor!

I had several experiences with exhaust nuts coming loose on-track, where vibrations and forces are pretty extreme relative to street driving. Eventually I completely lost a megaphone at-speed which thankfully didn't cause any damage to anyone's car but was destroyed. So now I have them safety-wired...