I changed to a newer lighter flywheel. I have replaced the rear main seal only 3k ago, and it doesn't leak. Can I accurately set end play with seal in? Yes I am a little lazy, but these can be a pain to install w/o leaks imho.

I think you can check it but if you have to change shims you'll have to pull it. By the way an old stub axle is just the right diameter to use to drive a new one in. It makes it easier to drive it in straight.

And thanks for the installer tip Dave!

IMHO if you don't do it, and it leaks you will have to pull it all apart right after

you pull your own foot out of your butt. They are not that hard to change

and not very expensive. But that is me.