I like that one. Saves a lot of time resurfacing the old one, this is ready for body match color, plus no welding either.

I have to agree that $42 seems high for that conversion "kit".

 

Just a thought, might have a plugged vent tube so the pressure builds in it and pushes oil out your rear.
My rear didn't use to leak. I've had a leaky rear for several years now though. I hate having a leaky rear.
Here's another company.
http://www.oasisdifferentialcovers.com/dodge.html