Diesel Bombers - New owner of a 1992 D250 Cummins

Well I blew up my ford in july and decided I wanted something that would last so I bought a 1992 D250 Cummins with an automatic 2wd. about 260,000 miles on it. I am excited to own a diesel for the first time but don't know a whole lot about em. Been doing my research as needed but anyone with 12v knowledge would be a great help as things arise.
Current head scratchers are: which of the three relays under the hood driver's side is the starter relay? I have had to cross the starter a few times when I bump a curb while parking and was told this might be a good place to start. I have what I think is the fuel shut off solenoid dripping fuel always and want to know what the steps are to replace that. read somewhere the a $10 part may be all I need and can be found here $10 Magnetic Valve (Start/Stop Solenoid) for VW Diesel Injector Pumps. VW Diesel TDI but I'm not too confident with that assumption. Next is my transmission. Its the 618 with lock up but if I don't let it warm up sufficiently it will start slipping within a half mile of my house in the morning. Is this a standard Auto problem of needing a fluid change or am I looking at bigger problems. readers should know that the shift indicator is off and my dad drove it in 2nd unknowingly for quite a ways one night. I have noticed a slight trans fluid drip from the pan and if I remember right the previous owner changed the fluid and filter while he owned it (a year ago). I have read that the dodge trans need pretty regular maintenance (fluid change, band adjustments) otherwise they live up to their poor performance and failure reputation.
Other than that if there are any cold weather tips for for my 12v to keep it running through the winter I would appreciate it. I live in Nebraska so its not the worst but it gets pretty damn cold.
Thanks all.