What I learned while battling my rear main seal leak:
-two piece rear main seals may suck, but at least I don't have to remove the trans like I would for the 1 piece design that the 2.5L has.
-be certain to add silicone *everywhere* the manual says and make sure you add plenty (but not so much that you get it where it shouldn't be)
-When the Haynes manual directs you to an earlier chapter for oil pump installation, don't start believing that the 4.0L has a gasket for it like the drawing shows. That's a 2.5L thing. (maybe. I can't verify that cause I don't have one)
-If you injure the upper half of the rear main seal in ANY way, stop yourself right there and go buy another! (If I had to do this again, I'd buy two from the start and then return the other if the first one works) Between my lift (and probably the Ford suspension parts), I can drop the pan without jacking up the truck or unbolting anything but the starter. If your truck is stock-ish, doing it right the first time is of the utmost importance!!! I can't imagine having to disassemble my suspension each time I tried something new.
-just because it doesn't leak while sitting there idling, doesn't mean it won't spew oil like the Exxon Valdez when you hit the pavement and put a load on the engine. Go test drive it now rather than when you go to work the next day!
-If you are fighting a rear main leak rather than just a leaky oil pan, I advise you to use either a cork or the one piece rubber oil pan gaskets. You do NOT want to scrape RTV off the engine more times than you absolutely have to. If you use a cork gasket, I'd recommend using a small bead of silicone to adhere it to the oil pan (smoosh it down good and let it cure before attepting to re-install the pan). This way the gasket peices will stay on the oil pan during installation (and removal and installation and removal and installation and... well, you get the idea. I dropped the pan 4 times but only had to clean the mating surfaces once. )
-full goggles are waaaay better than safety glasses when staring up at a dirty, oily, rusty engine bay. Ear plugs and a must too (you don't want any rust or grime falling in there), and I heard keeping your mouth closed is definitely a plus.
-Let your engine sit for as long as you possibly can before removing the oil pan. Oil will slowly drip out of the engine for hours after it last ran. Overnight would be good, but you'll still have a few drips (hence the goggles) Laying some cardboard down under the engine is a good way to catch and absorb the inevitable drips.
-Old gasket removal: Whatever was used previously for the oil pan gasket had hardened itself to my engine block. I started with a rectangle razor, then moved to a *narrow* chisel (like 1/4" wide), then whipped out the air grinder with those brillo-lookin' pads. The pads clog fast, so first scape off everything you can before using them. I used a small piece of cardboard to deflect the spinning crap from my engine innards. Other methods most certainly exist, but that's what I had on hand and it worked for me.
-Having a fan blow a gentle breeze on you while you're under the truck is a definite plus in my book!
When you sweat, little bits of "stuff" falling off your truck start *adhering* to your face instead of bouncing off.
-A rolling cart is nice for lying on and getting around at all those bolts, but a large piece of cardboard raided from the local recycling drop-off center works too. Just make sure that you're not lying on the cardboard that's absorbing the oil droplets.
-Don't be like me and paint your oil pan gloss black! It's *impossible* to tell where any oil trails are coming from.
-And my favorite one of all: There are lots of ways people might suggest for lubing up the upper half of the rear main seal for insertion, but I think I found the best. I used my grease gun to absolutely fill the upper chamber and then added a bit of grease on the seal itself just for good measure. It was sooooo much easier than only smearing the seal with grease or vasoline or oil and then trying to dab a bit up in the hole with your finger.
I dropped the pan 4 times before I finally vanquished the evil rear-main-leak monster, but in the end *I WON*!!
Woo-hoo! I can drive my truck again! (It had quickly degraded to where I was losing a quart every 20 miles or so)
Jeep on!
--Pete
