Need to ID a Transmission

Well the salvage yard wanted $125 plus $25 core, so a total of $144 after tax and military discount. So I went ahead with my gut feeling and got it today.
One website noted:
4505170 - ‘89Chrysler,Diplomat&PlymouthPass.,A999

The full number is PK4505170 9937 9574

I was told the second number is a 10,000 day calender so I decoded it at October 11, 1988, by using this website: http://maxwedge.com/articles/10k.php
Pretty much spot on. So I'm tearing into right now.