A guy I know had a 93 3/4 ton ext cab diesel that he was very, VERY hard on, finally last fall it "quit" on him. I don't know what happaned but i assumed he overheated it for the umpteenth time and cracked a head or it went tight or something. He said the tranny was shot too so he just wanted to get rid of it, my bro-in law said he'd take it for his salvage yard so I picked it up. Just for ****s me and my dad started messing with it. Charged the batteries up and eventually it started. Shut it off and put some oil and coolant in and messed around with it the entire day. A few questions.

He consistantly overheated it and blamed the radiator, we took the thermostat out and had no problems with it all day. Would this make the ECU think the engine is cold and adjust for it?

Smokes a lot, mainly white witha little blue. Wondering if this is related to the thermostat out.

Transmision is almost brand new, he had it rebuilt a month before it "died". The problem is in the transfer case. Are the Tcase's the same as in a gas and what kind of tranny would be in there?

It starts very hard. Like its ready to catch but doesn't. It seems when its starting to catch pumping it helps. Whats the most likely culprit?

Whats the easiest way to tell if the head is cracked? Nothing appears to be leaking into each other.

n241 IIRC, same as a gasser tcase from a 1500-3500 srw. Test the Ohms on the glows. .8-1.4 ohms is ok higher than that doesn't get hot enough.

mine does the "almost" starting bit when the batteries are low or bad. I replaced both the batteries in mine and it doesn't do it anymore. This just gives the starter that little extra help it needs. Another thing you can try is going to a 5W-40 synthetic oil. This will also give the starter back some of its torque

Bad battery connections are a problem on these trucks.

Bad battery connections are a problem on these trucks.
Yes, good call QM. I cut off all the red and black rubber off of the terminals. Some of the rubber melts and impairs contact.

Well like i said this is a freebie truck so i'm just trying to see if i can get the major kinks worked out, I've been cranking it over with a HD charger on it and it doesn't make much difference except you can crank it longer when it doesn't want to start.

A compression check will tell the tale. It should be ~400 PSI on all 8 but test the glows first.

QM, when testing the glows, do you have to disconnect them? I used a circuit tester hooked up to the positive terminal to test mine. All conducted current. I didn't unplug them, though...should that matter?

Ohms are more accurate than a 12v test light. Most of the ones I've replaced would light a 12v test light but were in the 1.5-3 ohm range

You might as well replace them all. They are not that expensive and that way you will know they are all the same glow plugs and the same age as well.