Maytag atlantis tub seal replacement

I sure could use some help. I am reassembling the washer & am trying to install the new tub seal. The thread fit is extremely tight. I removed the old one by driving it off with a punch & hammer. Is this how I should install the new one? Drive it back on?

Also I could not remove the old seal nut without chiseling it out in pieces. What is the best method of installing the new one? I have the plastic adapter that fits over the tab but I have no ida how to tighe it down without damage.

I’m told the spanner wrench that should be used for these two parts is no longer available.

Thanks for the help

Here are your parts
http://www.appliancepartspros.com/partsearch/modelsearch.aspx?model=MAV6650AWW

If you click on the seal kit a new page will open with a Q&A that may be helpful.

Also here is an Atlantis manual. Even though your unit is not listed with a little luck it will be close.
http://appliancejunk.com/forums/index.php?action=downloads;sa=view;down=115

See the attachments for a couple tech bulletins.