Well not to put a damper on things, but if yours has the two piece seal like mine does...it's darn near impossible to change it with the engine in the truck. You will have to remove trans, and clutch and flywheel to get to the top half of the seal, but removing the flywheel is its own set of challenges if the bolts are seized into the crank like mine were....it's a horrible horrible job...LOL....sorry, just trying to be honest...I just replaced bottom 1/2 of mine this spring, that was enough to fix the problem, but I just got lucky, as it was changed already once when I rebuilt the engine.
if it's the 1 piece, then you should be able to roll it in, so oil pan set, some tie wire to put back on the main bearing bolts and some ultra black is always handy for the oil pan corners