I'm curious about this little shortcut repair too. I just did my headgaskets and resealed the timing cover and pan too. I had a leak at the back but when I pulled the pan the rear of it was dry so I assumed it was coming from the valley gasket or the valve covers so I didn't install the cruciform seals I had bought. Now that it is all together I have oil at the pan/tranny joint again. Adding a bottle of something while changing the oil sure sounds like a good approach at this point!

 

it actually took me two oil changes and two bottles of white sheppard for the rear main seal on my RRC, but the truck had been sitting for like 8 years.

 

As I mentioned in my post on 8-13-13 I used the white shepherd/blue devil rear main seal fix my substantial oil leak and worked exactly as advertised. I'm happy to report that over a year later and 11k miles, (and many, many, bumper crushing off road adventures) there is still not one drop of oil coming out of my 2001 rebuilt engine. If you suspect a rear main seal leak, buy the stuff!