RamDodgeSam

Ran up to the hardware store, with no problems. I'm back outside in 20 minutes and start the truck up which starts up just as quickly as normal except horrible knocking sound. I can't tell if it's thrown rod, injector quit or plugged, or cam sensor got thrown out of place or what. Not knowing what it is I've only run the truck for a couple seconds a few times just to get a good listen. Sounds like knocking in a hollow space. Can't locate the sound yet.

Any ideas? Worst case scenario of course is internal damage like a hot piston that fused to the wall. But what's the first thing to consider. Very grateful for any help.

Mexstan

Any smoke? It's hard to diagnose with this minimal info, but will take a couple of wild guesses. My first guess is a bad injector. Did you check the oil level and smell the oil?

Is this an automatic? If so, could the flex plate have broken?

It would help a lot if you gave us some details of the truck. Suggest that you fill in your signature.

RamDodgeSam

The sound is a knocking consistent with RPM of engine. Sounds like something hitting inside a hollow space, so flex plate is possibility. would be weird to happen after parking it with no problems before but I'll check tonight.

While spinning back down after killing ignition, a faint metal to metal raspy sound is audible once the sound of combustion is gone.

Could be bad injector but get this, truck ran strong and idled smoothly before. I guess it's possible for injector malfunction to be greater under load when i wouldn't notice it as much. So perhaps I've burned a piston.

Smoke seems normal for start up. What would a bad solenoid sound like?

Edit: meant to update with this post. a Friend pulled me the 3 or 4 miles home and the goat is parked safely outside my house. On the way home, I didn't noticed any funny drivetrain noises.

soulezoo

Sounds like a rod bearing went. If this happened due to momentary oil starvation, then piston scoring to cylinder is also likely.

Maybe a dropped valve seat, although I am not sure on a 04.5. On a 03-04, that is a definite possibility.

RamDodgeSam

I went out to remove the small cover under torque converter to inspect and got to a point where I could not turn the engine over by hand (using a large flathead barring one tooth at a time). SO that sucks. Hoping for a transmission problem. Flex plate appears fine though.

So weird since the truck sounded and drove completely normally before parking it 20 minutes before the problem arose. at the very least i'm definitely going to have a look under the valve cover this week.

for the few seconds ive run the engine under this condition, the idle speed is steady and the combustion does not sound irregular so i'm leaning away from injector problems - although those will probably get some attention anyway when this whole mess gets sorted out.

1-2-3

Not being able to turn over the engine means nothing. They have alot of compression. Did you get gas while out on your trip? Gas?

RamDodgeSam

no the engine stopped on something hard. Not on compression. Never gave too much thought about putting gas in these things - I just use it cuz it's cheaper.

edit: joking aside, no. never been a drop of gas in it

soulezoo

Use a breaker bar and socket on the front nut at the harmonic balancer to bar the motor over.

It's sounding a little more like rod/main bearings with melted piston.

Keep us up to date with what you find out.

Drain the oil and see if there is debris in your oil; that will confirm the above. If not, maybe that dropped valve seat.