Dude, do yourself a favor and look at the research [MENTION=78997]Drcoffee[/MENTION] has done for us. He shows in a short video that the lip of the new seal design sits a little more inboard towards the differential compared to the original design. If you keep the retainer in the same spot on the axle, based off FSM spec, you DO run the risk of having a leak again. I stupidly let my local Toyota dealership do my rear axle seal job and one of their top mechanics for this job screwed it up. Luckily, again due to [MENTION=78997]Drcoffee[/MENTION], I knew how to check if the axle seal was holding by pulling the ABS sensor and looking inside the axle. After only 500 miles, there was already a little gear oil accumulating on my driver's side where it shouldn't be. The mechanic didn't even know about the grease test. I had them do the grease test right in front of me and it showed the lip of the seal was riding right on the edge of the bevel. Per my request, they flipped the retainers and did the grease test to verify where the lip of the seal was riding. I now have around 10,000 miles on this repair with no problems.
I think most people don't realize their axle seal repair is already leaking because they don't know about the ABS sensor trick and it takes time for the gear oil to finally make it's way into the brakes and start giving you symptoms that something isn't right.
Whatever way you chose to go, make sure you do the grease test before you bolt everything back together.