Basically you need 2 people to make it easy.

To replace it, you need to pull the shifter unit up, into the cab. You disconnect the linkage (cotter pins) from the tranny and tcase shifter, then you label and disconnect the 6 or so wire/plugs, label them 1-6 so that they go back together properly.

This takes about 15 minutes. All this is covered in a boot, covered in dust/mud, so you need to wear eye protection.

The shifter comes out witn a deep well 7/16" socket from the underside and an allen screw from above. You can skip the buddy with a couple of vice grips.

Then you pull it out and screw in the new one, and put it back together.

The glow plug controller varies by model, and is just an unplug and unbolt and reinstall. Some are cheap, and your's might be fine. If yours works (the voltmeter/battery voltage will drop when the light is on) it is probably fine, if you replace it (easy) throw the old one under the seat and keep it as a spare if you are travelling and need one. Do the same with your serpentine belts.

For diesels to start, you need fuel, engine speed, air, and heat. So your glow plugs need to work. On a cold day you can get by with 6 of 8 working, but if it's colder, you probably are out of luck.

So you need to check for both voltage to each plug, and resistance in each plug.

Since most (if not all) work, check the resistance of one, and the others should match. If no voltage at the end of the wire, figure out what is bad.

The wires are cheaey, and the connectors fall off, so it could be simple.

As for the starter, it needs to spin fast or good plugs, and good batteries, and a good NSS and glow plug controller wont matter, it wont start.

So if charged batteries and a jump wont start it, the starter is on it's last legs.

The engine can be plugged in, and it should gurgle. If it doesnt, measure the resistance acrosss the plug. It should be around 25 ohms or around 500 watts.

This is worth doing yourself, you'll know more about your truck.

John A.