Okay I've got a 2004 DII that I'm pulling the motor and dropping in a 2002 Range Rover (I'm pretty sure it's a P38) anyhow they are both 4.6's with secondary air. I am planning on doing valve cover's, front crank seal and pulling pan to clean sump pick-up and then obviously a new oil pan gasket. I had debated about doing the rear crank seal, on one forum was told if it's not leaking they would leave it alone, "to much chance for mischief" one said. Another forum said they would definately do it. So I guess you all are the tie-breaker. So I would appreciate your takes on this and anything else you would if it were your own. Thanks,BDC

 

I would change front and rear crank seals. I had 2 front crank seals go bad on mine. I just put a 3rd. when I changed the front cover gasket and timing set. If a rear seal goes out you have to pull the engine or transmission. Replace your oil seperator and clean the pcv hoses while your at it. Also loctite the valve cover bolts.

Willie

Willie

 

personally, i don't know much about what your doing, but if it were me id change it for "peace at mind"

 

I would change it while the engine is out of the truck.
Odds are your fine, but if your not you will be kicking yourself later.