When i go to start the truck, it just clicks

Take the starter off and go through it again, with a no crank condition its pretty simple in that there is only a few components that are going to prevent cranking over, starter and starter solenoid, battery, and ignition switch. If its clicking thats most likely the starter solenoid clicking but the starter motor isn't spinning. Bench testing a starter only tells you that it will spin without any load on it, but on the engine it might not have enough power to spin. Check all cables, clean all connections, check voltage at the starter terminals and compare to the battery voltage, if there is a big difference you have a bad connection somewhere causing voltage drop.

If all else fails get a new starter since its a new battery and go from there. Having it out on the bench without a load might have got it unstuck and working again, still sounds like a failing starter. Try giving the starter a few taps with a hammer on the side and try starting again to see if its stuck.

the glow plug circuit may be faulty, check glow relay and timer function, or connection to glow plugs, the glow plugs may also be faulty, if all is well with them, then you may want to check the fuel injection pump it may have a worn hydraulic head. To start you can try some quick start fluid but disconnect the glow plugs first,

Don't just keep cranking if it don't start right away' Give the starter a break. It's getting hot because you just keep cranking on it. Any vehicle diesel has glow plugs to heat the fuel chamber to make it start fast. Be sure you are making use of the glow plugs and it will start fast. If your glow plugs are not working, find out why. Could be just the glow plug relay or connection to it. Or possibly the glow plugs are burned out. Either way, you HAVE to have glow plugs in use on a diesel upon initial start up till it's warmed up. Then will start without them. Most are automated system. You just have to wait till the glow plug light goes out to start cranking on it. I hope this helps you to more understand the workings of a diesel cold start system.

The solenoid click sounds very strong, implying that you have a charged battery and the ignition circuit is functioning out to the solenoid. Suspect an issue with the starter motor. Is the starter motor installed and connected properly?

Hello Hugh, You need to check the voltage at the glow plugs.. Just because you hear the relay clicking does not mean it is working properly.

I would try changing your fuel filter. Inspect the fuel lines for leaks. Air getting in the line would cause fuel to flow back into the tank.
I really suspect that the long cranking time may be a problem not with the fuel system but with the glow plugs, You probably need to replace the plugs as they are not pre-heating the combustion chamber properly to allow ignition of the diesel fuel. To start a diesel motor with out glow plugs you have to crank the motor until enough heat is generated to ignite the fuel. Glow plugs are not very expensive and fairly easy to change your self.

Make Sure the Battery is Fully Charged,This can be done by Headlights or Horn.OK.

if you have changed the glow plugs and it still plays up try changing the leads that run to each glow plug if that doesnt help theres a pre heat box relay which is for the glow plugs should be somwhere near inner wing check it is clicking over after you turn the ignition to start position youll get the pre heat light on the dash once that goes listen ans you should here the box click .hope i could help

Sounds like the glow plugs are frazzled. There is one electrical wire going to a plug, then each plug is connected in sequence. The glow plugs are heating devices used to get the fuel up to temperature before ignition.

They are fiddly to replace, but are relatively inexpensive and the most common source of issues with cold-starting diesel engines (first thing to fail).

Some cars had a 'pre-heat' available with glow plugs, where you simply turn the key part-way to 'on' and you would see a glow plug light come on (looks a bit like a picture of a spring). If you see this light on your van, you can turn the key to turn on the glow plugs and they will pre-heat your engine slightly and make starting easier

HAVE YOU REPLACED ALL YOUR GLOW PLUGS RECENTLY? EVEN THOUGH THE GLOW PLUGS APEAR TO BE WORKING I FIND WITH AGE THEY NO LONGER HEAT UP QUICKLY ENOUGH BEFORE CONTROLER TIMES OUT. THEREFOR CREATES A HARD OR NO START CONDITION.