Well I finally got fed-up with the leaky Moroso pan so I pulled it off today and installed the 4X4 pan I had bought a few months ago. I looked the Moroso pan over after I cleaned it and couldn't find any obvious reasons why it was leaking. I searched this forum and found a link to one of the other forums where a lot of guys were having the same issue. I called Moroso a few minutes ago and they told me to mark where I thought it was leaking from and send it to them so they could inspect it. So that's what I'm gonna do. I don't expect much, but it worth a try. Plus, maybe it'll shine some light on their QC department and maybe they'll fix this issue in future pans.

Moroso Trans Pan.. leaking? - F150online Forums

 

I just got a Moroso pan about a month ago, now you've got me paranoid. My personal opinion is that when the rest of the pan was welded to the flange at the top, the flange might have warped. If mine leaks I will take it off and indicate it to see if it is warped.

 

I checked mine with a straight edge before I installed it and it was fine. It wasn't leaking from up where the gasket was so I don't think it was the rail. It was leaking from the welds.

 

That wouldn't tell you if the flange was twisted. Could be the tranny flange not being straight as well...

I've posted this before, but my casted AL pan never leaked on the first two transmissions but leaks like crazy on my current one even with a new gasket.

 

Mine leaked from the weld... they told me the same thing, to ship it back to them. They told me they would send me a new one, but it looked like they just 'fixed' mine and sent it back. I ended up with the 4x4 pan instead.

 

Update: I've been running the 4X4 pan for a few days and I crawled under the L this morning and there isn't any sign of trans fluid. This tells me that the Moroso was definitely defective.