hello does anyone know if the rear seal is one seal or a two part seal? my auto parts supplier provided me with a oil pan seal(main) for engine up to 2006, he said there is no difference.

 

I am doing my rear crank seal on my 2001 4.0 sohc and mine is one piece but i don't know if yours is the same

 

Crank shaft seal on either end of an engine needs to be one piece, these are called front or rear Main Seals
Oil pan seal isn't called a Main Seal, just an oil pan seal/gasket.

So make sure you and the auto parts supplier are on the same page, talking about the same seal or part.