Re: Rear motor mount bolt loose
Yes there is a slot that should hold a captured nut. The nut slides in with the open end facing up and the nylock end at the bottom. I hope you still have the washers, spacers and disc still captured on the bolt. If you do it's easier to fix. Either way you will need to pull the drive to recheck alignment. Once the drive is off loosen the other 3 mounts to lift things enough to put the stack back in there properly.
I don't think you will be able to slip the bolt past the mount and get it started in the nut without backing off the other mount hardware tension. If it won't line up you might have to give the engine a shove to get everything in place. If it still won't go you might need to do a partial lift of the motor so it will move to where you need. Once everything is started, torque, check engine alignment, and install the drive.