Yeah, that. ^^ Good Idea.

 

Just did this job on my 5.2L Dakota. I had a leaky rear main seal which was spraying oil all over the transmission bellhousing. All of the above recommendations are correct. I replaced my pump and pickup tube, used the Melling high volume pump. Do the rear main seal while you are in there, make sure you offset the two halves of the new seal about a 1/4" when you put them back in (the package for the seal should mention this as well). That way the points where the two seals come together are inside the bearing caps and can't leak out the back of the pan and along the crank. Get the good rubber pan gasket, its about $30 at your local parts store. Don't forget to prime the oil pump, as HeyYou mentioned it is easy. Just pour a little oil in and use an Allen to turn the pump a couple times until you get just a little bit of oil coming out of the pickup tube. Check Rockauto.com for all the parts, got great prices on all items shipped to my doorstep.

After replacing the pump, rear main and pan gasket, my oil pressure stays high constantly per the gauge (about 2/3rds on gauge). Prior to doing this job, it would be high while I was moving, but if I stopped at a light it would drop down to about 1/3 on the gauge. Here is a good writeup on the rear main and basically the entire job when you decide to do it:

http://www.pavementsucks.com/tech-article-31.html

Use the fishing line trick when you go to put the pan and gasket back on the motor. Tie some fishing line on the four corners of the pan/gasket combo to hold the gasket in place as you line it up on the motor. Also make some alignment dowels out of 5/16" bolts, 1 1/2" long. Cut off the hex head top and use a grinder to cut a slot for a flathead screwdriver. Screw these in to the four corners of where the pan meets the motor, then use those to help you align the pan/gasket combo on the motor. Makes the job 10x easier, that gasket likes to move pretty easily! Don't forget a little RTV in the corners as mentioned in the pavementsucks.com article, and the Loctite on the bearing cap. Loosening the next two caps toward the front of the crank made removing and installing the rear main much easier.