272c cat skid steer lost all hydraulic function

Hello, first post so bare with me. 2010 cat 272c wheeled skid loader yard hand was operating it said he heard a quick nose( he could not describe the noise) and lost all hydraulic functions wouldn’t drive move arm bucket ect zero function. After playing with the switches and checking fuses and some wiring decided to crack a couple lines lose while running see if we were getting anything zero pressure skip ahead pulled the motor and I’m going to call it the coupler that connects the pump shaft to the rotating assembly of the motor was free spinning and while pulling said engine noticed the 2 bolts holding the pump onto the “ bell housing” missing my question is how do I reassemble this plastic plate and gear guys at the parts counter said the metal center section supposed to go on the pump shaft first and plastic ring on flywheel but how do you keep it from falling back off it was pushed all the way into behind the plastic plate up against the flywheel I’m going to try to figure out how to post a couple pictures first pic going to be the position it was sitting in when I found it but any help advice or trick to putting this back in would be appreciated first skid steer engine pull here