My '87 has developed a shudder in drive when above 40 mph or so in highway driving. If I put it in OD the shudder or shimmy goes away. I had a converter put in about a year ago,so I don't think its related to that,so does anyone have any ideas? Under hard,constant acceleration,the problem does not occur,its usually when backing down off the gas and cruising between 40-55 mph. Again if I nail it,it dissappears. Thanks all. Tony T