Resurrecting a very old thread here for those who are interested. 912A585 is the part number for the JL Dana 30 M186 front end's Truetrac and the installation kit is K-D30-186. The JL Dana 44 M220 rear end's Truetrac part number is 917A736 and the installation kit is K-D44-220...
John (Cappa) is an automotive journalist. He was the Editor of Jp Magazine and Four Wheeler Magazine. Now he answers tech questions in both mags. If you can get him to answer questions here, he would be a great source.