As another person noted, the TST kit uses a tab method and is satisfactory and priced reasonably vs. rental of a jig. More importantly, the TST method involves removal of the cover whereas the jig method just drills through the case from outside it. Removal of the gear case cover allows you to check the tightness of the bolts inside it, and preferably remove, clean, and loctite them into place. The five bolts holding the gar case to the block are most susceptible to loosening. If one falls out, its flange head can catch between gear teeth and result in even greater damage than the killer dowel pin causes (the dowel is too big in diameter to fall between the teeth and lock up the engine). You can get directly on two of the bolts, two more are accessible through “windows” in the cam gear if the engine is cranked over so one of the three windows exposes the bolt, and the fifth can be reached (but not removed) to tighten it with a bent open end wrench through one of the windows (it is farther outboard, toward the gear teeth). The two cam retainer bolts and four oil pump bolts do not usually loosen but should be checked. Yes, the fan hub has left hand threads in the first and second generation trucks.