But yeah,
@dbrannon79 , that's a symptom of an alternator on its last legs. My Burb did that same thing a couple of times, then was fine for a couple of weeks.
Was headed to NYC with some friends and stopped off in west Joliet, IL to top off, as fuel was about 30 cents a gallon cheaper than on the Indiana and Ohio Turnpike service plazas. Any how, got back on I-80 and almost immediately noticed that the voltage gauge was reading about 12 and the tach wasn't working.
After a brief, heated discussion among the four of us that I won as the driver and owner of the Burb of why we didn't need to find a truckstop to work on my diesel engine/replace the alternator, one of my buddies Googled for the nearest auto parts store (an Advanced Auto) off the next exit and a couple of miles into Joliet.
Long story short, pulled into the AA, went inside and asked the parts guy if they had the specific alternator in stock for a '98 6.5TD, he asked me standard or the HD rated one. I said HD if he had it, and if he was looking at the 6.5 application, that while a gasser will bolt in, the pulley sizes are different and it throws the tach off. He had the correct HD alternator sitting there on the shelf! I then amazed my friends when I grabbed my travel tool box out of the back from under our luggage (I ALWAYS carry a pretty complete set of hand tools - ⅜&½ drive SAE&Metric deep and shallow sockets, Torx bit sockets, various length extensions, ratchets, breaker bar, SAE&Metric combination wrenches, 24" prybar, ball pein hammer, 2lb hand sledge and a full assortment of sizes and lengths of Phillips and straight screwdrivers and a cheap code reader, VOM and test light and a small butane torch/soldering iron, solder and a small crimper and connector set in a 24", three drawer tool box whenever I travel anywhere in any of my vehicles), pulled the old alternator right there in Advanced Auto's parking lot took it in, got it tested, confirmed it was dead, bought the HD alt for $128 including the core trade, took it out and installed it, and we were back out on the road and headed to NYC an hour after noticing the alternator was dead and my buddies were amazed at both my carrying a full set of tools, but being able to get everything fixed and back on the road.
So yeah,
@dbrannon79, I'd say that alternator is on its last legs.