Sorry it took me a while to get back to you, I haven't been on this site for a while. I'm just finishing up my Associate's degree (took my last final last night, woohoo!!!!!), and Skoolie.net tends to suck me in. I start reading posts, and next thing I know, I've been on here for 5 hours or something.
Anyway, the T444E. Some love it, some hate it. It's the same engine as the Ford Powerstroke, so it's super easy to get parts for. The only major issue I've seen with them is injectors, but it's not a huge job to swap them out. If it starts skipping, running rough, or losing power, that's probably the culprit. If you do have any issues, ask in the Professional Garage over at www.schooolbusfleet.com/forum
. Those guys are great, and a lot of them have experience with the 444. Whether they love it or hate it, it was a very popular engine. As for maintenance, just do the oil and filters and keep an eye out for anything major.
In the battery box near the right rear wheel, you'll see there are a couple of plugs and fuses on smaller wires than the battery cables. These power the ECM directly off the battery. It's also not a bad idea to disconnect the main battery cable if you're going to weld, or if the bus is going to sit for a while. I'm not thrilled about how the cables are arranged (on an older bus, you could just pull one main cable to cut all power), and I plan to install a shut-off switch at some point.
Does yours have the 2000 series transmission? (5-speed with a lockup converter, shifter would be labeled D421 instead of D321.) If it's a 2002 it probably does, and I'm jealous. I have the AT-545 "slushpump," a 4-speed without a lockup. She moves along pretty well considering, but there's a lot of power and economy lost with that transmission.