So I have a known front tranny seal leak.  In an attempt to remedy this I dropped the tranny and tcase last weekend and found that the lube was getting by the felt seal and seeping down the tube then in to the bell housing then out.  This was a brand new seal that came in a Crown kit.  So in my thinking, I thought I bet if it was slightly thicker, it might make it seal up a little better.  I made another donut out of some thinner felt I had and added behind the other felt seal.  It was a bit snugger on the output shaft when the bearing retainer was bolted back on.  Fast forward to it still leaks about the same amount. I get about a 3-4" puddle after a drive.
So, I am now wanting to have another go at this but hope to go in more prepared.  I have read up a bit and found some have used a sealed bearing in place of the open type and thought about going that route. 
Anyone have any tips or suggestions?

Carl,
I'm not sure what vent you are talking about, do you mean the vent on the tcase?  That one is clear and no, the cases are filled to where they should be to the bottoms of the fill plugs.

Yes,
some bearing part #s are
SKF 6208 2RSNRJEM
MRC 208 SZZG

From the forums I have read, the SKF---6208-2RSNRJ/EM, is what others have used.  If that cant be found the MRC 208-SZZG is an equivalent.  Both of which aren't too easy to track down.
I have also come across a brand called Nachi bearings and have found that their 6208-2NSENR is a fit also.  I have never heard of Nachi but a bit of searching shows their bearings have been used in various applications.  They are a Japanese bearing,  I wont buy any bearings from China.  Anyone have any info or first hand experience of their bearings?
With searching this info, I find it interesting that the bearing unit used in these boxes is metric.
40mm X 80mm X 18mm (1.5748in X 3.1496in X 0.7086in)  I measured that against a bearing I have on hand that was replaced on the rebuild and its right at that.
As soon as I obtain a bearing and get time, I will get this done and do a flup with pics.

The SKF bearings are made in several Countries including China and Hong Kong so it will be a toss up where your bearing will be from.

The next important things is a SKF 6208 comes with and without a snap ring groove and you NEED a groove.

The SKF 6208 2RSJEM is a double seal without a snap ring groove.

The SKF 6208 2RSNRJEM is a double seal WITH a snap ring groove.

If you do not specify the correct number with the correct suffix letters you may not get the bearing you need. When ordering a bearing you can;t just order using the basic numbers, you have to use all the numbers and letters to designate the style bearing you want.

It has to have a snap ring groove to use in the T90 tranny. You could leave both seals in the bearing but I suggest you remove the seal that would be on the inside of the tranny.

Good job, just wanted to be sure you had the right numbers. Sometimes it's hard to get the right bearing because different makers use different designations.

Well, I think I might be getting too good at dropping the gear boxes.  Took me all but an hour to pull everything and drop them down.  With support from above and below it is a very controlled move.  And I was able to remove  the bearing from the front end with a little persuasion.  Now I have to wait for the bearing to come.

Bretto,
  As I have followed this thread I have ached for you.  I have had reason to pull my transmission too many times already (each one has been posted here, as well). It's not fun.  But when I saw your photo above (with the strap support from your garage ceiling) the photo revealed the large floor section that is removable in the M38 (as with the other military Jeeps), I quit aching for you so much.  How nice it would be to have that big section of the floor out of the way when you need to R & R the transmission.  That's almost as nice as having the tub out of the way.  I have said a couple of times before, here on the CJ-3A page, that if I had to do it over again I would seek out an M38 to rebuild.  The big hole in the floor is just one reason.  Another is the spare tire mounted on the back where it belongs.  Another is the fully restored Jeep has the desirable OD paint which is much more forgivable than is my glossy yellow.
  I hope your sealed bearing does the job.  I don't know any way that it couldn't.  Good luck!!