No you don't HAVE to loosen them but it wouldn't hurt to have a little slack on them so I do remove the two lower long bolts through them, don't forget to put them back in when buttoning up the work when your done
I do put a short piece of 2x4 soft wood in between the oil pan and the steering drag link and oil pan between the idler arm and the steering box arm to support the middle of the motor while the trans is out