what is a good way to tell for sure if the rear main and the the back of the intatke is leaking?

 

Run you hand along the back of the intake where the intake joins with the block. You'll pull back an oily hand if the intake is leaking. The only good way to tell if the rear main seal is leaking is to pull the tranny. Also look along the valve covers where they meet the heads for leak sources.

 

Just pull off the bell housing of the tranny takes 5 min. and look at the rear main. while you are there take a flashlight and look at the back of the intake from under the car.

 

Before you start tearing into things, make sure it's not coming from the oil filter. I went through about the same thing. Went out and bought the RMS and everything. Thank god I found a small nick where my filter is supposed to seal. I woulda been a little upset to say the least if I would have spent the time pulling it apart to R2 the seal

 

The most common spot for the "back of the intake leak" is behind/under the EGR valve.