Basically just 5 or 10 minutes to remove the flex plate and the rear engine cover. Rear main seal mounts in the rear engine cover. While you're there replace the oil diverter, looks like a dog bone with o-rings that slides in. There's several nice aftermarket ones made of aluminum instead of the OEM plastic. The rear covers are not expensive.... Beats the hell out of cleaning your old one. You will want the centering tool, slides over the crankshaft and holds the rear cover centered while you tighten the cover down. Not necessary if you have the oil pan off. Speaking of which it's an excellent time to drop the oil pan and replace the o-ring on the pickup tube. If you're still running AFM, you want to replace the oil pressure relief valve that mounts inside the oil pan.
The old adage about why you're in there.... You kind of see where this is going? Once you have the oil pan off, that gets you started thinking about the front cover with the front crankshaft seal. Oil pump and timing set behind it, and so forth and so on. For some of us is difficult to stop, and not just continue on LOL
