Went outside this morning to start and turned the key and heard a loud click, like the solenoid. Starter won't turn. What could be wrong?? No ratcheting. Batteries seem fine.

 

The alternator is warm if that means anything. Still won't crank.

 

My first guess would be bad battery cables.

Mine drove me nuts starting one time just fine, then not starting the next time.
Turned out the passenger side battery terminal was toast inside the terminal.
Corrosion and burnt off conductor, I do not see how it had started for a year or so before I found it when I saw how bad it was inside. Looked fine on the outside, but there was a tell tale look of the cable had heated up close to the terminal.

If the insulation on the cable looks or feels brittle close to the battery terminal I think you can figure on a new set of cables.

 

Here's a good site on where to get battery cables.
http://www.custombatterycables.com/a...350_cables.htm

 

The starter has done this once before but right away would start on the second try. It is almost as if it was hung up or something. My passenger side neg cable is split and bulged a bit. Where do they connect?? Meaning, from the battery, the drivers side battery connects to the passenger, then the passenger to where??

 

The cable then goes straight down to a solenoid on the starter.
Both batteries have a ground cable that goes to the engine block individually.
If either ground cable is not making good contact, it will be like trying to start on one battery.

When it was doing this before possibly the first start attempt heated up the cable enough to make a better connection with the heat expansion of the conductor.

Once the connection is bad enough, it does not make good enough connection to make enough heat to expand the cable.

All power for the truck goes through the passenger side positive battery cable terminal.
The chassis power, alternator, second battery and starter all tie together in that one connector.

When mine kept doing funny stuff on me, letting me sit with what appeared to be a dead battery 10 minutes after it started fine I lost my cool.
When I looked at how stuff was connected, I saw that terminal was the key intersection.
I took a 4" grinder with a cut off wheel on it and cut the terminal open to expose the wire.
I could not believe what I saw inside a normal looking battery terminal from the outside.
The wire that goes to the starter from there is a 3/0 AWG wire that is about 1/2" in diameter.
That wire was burnt off over 1/2" in length inside the terminal.
Grab the wire that comes out of the battery terminal and shake it around, then try to start it again. Even better have someone else hold the key to the start position and shake the cable. If the connection is bad there it should make contact and start. If it pulls out or it does start, chech to see if the terminal is hot as soon as it starts. If it is hot, get a new cable before it lets you set somewhere.

 

Forgot to also mention, every electrical accessory, such as lights and radio function normally...

 

Glow plugs and starters draw more current in 10 seconds than every light and accessory on your truck will draw in several hours.
I was looking at starter draw numbers a while back, 3700 watts sticks in my mind.
My Silverstar headlights are 55 watts each, so the starter draws as much power as 67 Silverstar bulbs would all at once.
The glow plugs start off at about 2400 watts cold and then drop off some as they warm up. So the initial glow plug start would equal 43 more headlights.

 

Does interior lights dim or go out when you try to start the truck? If dims this is normal. Goes out then you have a bad connection as previously said.

You mention that the alternator is warm before you tried starting engine. I would say you have a short in the alternator. It should be cold until you start the engine then it will be warm. This would draw down the baterries to the point of no start situation.

 

Here's what i did today, to no success... Two new charged duralast batteries and new cable neg on the passenger side. Other cables looked in good condition. Went to start and same thing. Just a loud click. Made the key stay in start while bumped the cables around and nothing. Went under the truck and touched the starter... cold as i would have thought, but the little canister right next to it, assuming that is the solenoid was very warm after me trying to start the truck. Could the alternator have frozen itself and the starter is trying to turn but the alternator is holding everything up?? Tried moving the serpentine a bit and it wouldn't move at all. Could the motor be hydrolocked? I don't have any coolant in the oil. The cheapest starter was a bit short of $400. Knowing my luck alternators are just as much. The interior lights go dim like it the starter is at least drawing some current. I assume that would eliminate the starter then. The alternator is cold but when i attempt to start the truck it slowly warms up each time I try to crank it. It started and ran fine two nights ago, then the morning I came out and just a click...

 

Probably best to take the starter and alternator off and have them both tested at a starter/alt shop (save a trip by doing both at same time)

 

how do i get the alt. off? I mean, how do i get the tension off the belt??

 

Follow the belt around and there should be a belt tensioner which is spring loaded. Use a socket wrench on the nut in the center of the pulley and take the tension off the belt. Remove belt from alternator. Be careful as this is spring loaded and could do a lot of damage to your hand if it gets in the way.

 

FIXED!! Ended up being the starter like I had originally thought. Took the old one apart and there was a bunch of thick dark dust, like the magnet had disintegrated or something. $270 to Autozone and now I have a lifetime warrantied Duralast rebuilt starter...thanks for the help though. I now have two new batteries and cables...

 

Glad you finally got it fixed!