Just an FYI, Every magnum I've ever heard had a squeak in the belt. On my 93 Dakota, 96 Ram, and even my Cummins Ram, a little water on the belt made it go away for about 15 seconds. I've never figured it out, and my buddy spent a grand trying to get rid of it on his dad's 2011 Ram. He replaced everything in the system and it was there right on startup.
Some times this is caused by slightly out of alignment pulleys. I solved this by measuring the center lines of each on my Cummins, ended up putting a shim on the pulley for the alternator.
But you can also solve this by running a good year gator back belt. They don’t ride the groves and seem to work much better