My '69 SL automatic makes a rear end clunk sound when I slow down to a stop...it's much less after I adjusted a switch at the air flow butterfly near the air cleaner...I read there is an adjustment that is often mistaken for an idle screw that is used only for adjusting the shiftdown switch to the tranny...I had a hell of a time readjusting all the linkages and timing to get a smooth idle again and good performance, but there is still some clunking going on. So my question is, could there still be a trans adjustment required, or could I have too much rear axle lash now? I've heard this is a common thing on early MB automatics...