Ok all. I am having a hard time figuring this out.

I just put a used automatic tranny into my van. The tranny is fine,
but I can't seem to properly seal the differential oil pan (I
unsealed it to check the R&P gear). The first time I tried red RTV
and it didn't work. So I pulled it off and went with the expensive
($40) VW gasket. Within 350 miles, I had lost almost a quart of gear
oil and it got bad enough that I was had to stop every 50 miles to
add 15oz or so on my way across Washington. I looked like a dodge
caravan smoking my way around. I think the R&P is still OK though.

So, now I have an obviously bad (or badly installed) differential
gasket and need to figure out what to do now as stopping every 50
miles is not a good solution. Someone mentioned "the right stuff" and
I may try that next, but I need to stop leaving a trail of oil
everywhere I go. I'm wondering if it's me, the oil pan, or a
combination of both. I successfully used the red RTV on an oil pan
when I did a Subaru conversion (not this van) and had no leaks then.

I've looked at the pan and it isn't 100% flat...it's about 1/32 off
and rocks slightly from side to side but stops with a few pieces of
paper. The tranny sealing surface has no obvious issues and looks
flat. I can't imagine the 1/32nd being the issue, but who knows. Any
other suggestions. If it's the right stuff, any suggestions on
application methods (how much, etc) to use? I'd like to only do it
once as the stuff is a pain to get off!!!

Thanks!
Aaron
'85 Westfalia