Originally Posted by Caddyshack

Try and stick to the correct terminology as it will avoid wrong advice...it is the front diff cover that you are taking off (not transmission cover or transfer case)
The circlip is in the inside of the front diff.
To seal it up I just used Halfords instant gasket sealer in a tube that self propels itself out.
If you are going big power it is worth adding in the brackets that support the front diff from Burtons as they bolt to the block and then add the strengthening plate as it helps protect the diff.
I bought a good kit which is the metal straps for sealing the boots to the car, it is like a metal cable tie and came with special cutters which tighten the strap, I can post you a few of the straps if you want, you could tighten and cut them with pliers.