I've been deliberately keeping the car off the track thinking it's going to implode (or explode for that matter) but apparently it's not doing any damage, but it sounds so bloody awful. As for the rattle in neutral, Keith's post about the 5th gear clearances is absolutely correct. We'll be pulling the transmission in a couple of weeks and have a peek inside. If it is the reverse idler it's a $250 part. Not too bad but I don't think I'll be getting much change out of $1500 by the time it's all said and done. Although a louder exhaust and cranking up the volume on the stereo are cheaper options:) I'll keep you posted on what we find.

So, what does it cost just to replace the entire gear box?

Mmm...not sure. Others in this forum would have a better idea than me. You should be able to find a good one out there. A rebuild would cost around $1500 with new syncros and if the R+P is no good $3000. Hang on, that's about a third of the value of my car!