I have a 2010 JK manual no engine mods except air intake, 35" tires with 3" lift.
We were trialing threw the Rockies and driving threw a few low water spots ( about calf high) on our way out on was driving threw and all of a sudden it stall half way threw. I could not get it to start after that. Got it pulled out and all i could get was the starter to make the clunk sound. Once tried jumping it and nothing and even tried to roll start, but just the same clunk sound. left it parked and towed it back the next day. Had battery checked and was good, bench tested starter and was fine. Yes i know bench testing starter not a definitive check being no load but it was strong. Checked air filter and was dry, pulled spark plugs and where dry (broke 1 plug and a wire) but dry. Checked air tube and was dry and opened up Throttle body flap and dry. Checked grounds by doing a continuity test to ground cable connection to battery and found all good and physically checked ground to engine and found good. Battery posts a clean and good connections to posts. I have tried to manually turn flywheel and either i am to much of a weakling or im doing it wrong. Tried turning the crank with a breaker bar extension on a wrench with a socket and all i am doing is tightening the bolt or loosening it depending on direction. I have read check the ignition switch but looking threw the electrical schematic i am 100% sure its not that because i am getting the voltage to the starter.


Need help from anyone who has some ideas.


Sorry for the poor grammer and spelling.

 

Pull all the spark plugs out and try to turn it over. Check your oil and see if there is water in it.

 

I have checked the oil and bo water. I have pulled the plugs and stil just the clunk from starter.

 

From what you've posted, it sounds like something broke internally and locked up the engine. Drop the oil pan and take a look at the crank.

 

Drained oil, pulled pan and checked crank. Crank is fine.

 

There's gotta be a reason that the crank can't spin. If you have the plugs out, there's no compression and the motor should be fairly easy to spin. Since you can't, and the crank looks good from underneath, then pop the timing cover off and check there. Something is mechanically binding the crank from moving, there's not much that will do that.
The clutch is releasing off the flywheel, correct? Transmission in neutral?