well im in the same boat as you. i overheated my engine and now i have a knock in the back end of the engine. i already pulled the head off and the walls look good but one might have some scuffing. anyways so far the 2 back rod bearings look good. ill have to check out the wrist pins.

 

You could swap the injectors around to see if the noise follows it.

 

Your oil pressure seems a little low. Mine runs at idle what yours runs at accelerating. That would indicate rod bearings.

 

I wouldn't base any diagnosis off a Dodge oil pressure gauge. All that gauge tells you is that you have "some" oil pressure.

 

X2..Put a manual gauge on it, the factory sending units are bad for being slow to show pressure..

 

understood. Just making an observation, "assuming" consistency between trucks as my mileage is similar. A manual gauge is always better. I even bought one of those three gauge sets at harbor freight just to troubleshoot these things. Factory gauges are never on the money and are meant only to be an approximate indicator and not for troubleshooting.

 

Zee, In my KW with a Cummins Big Cam 4 #6 injector was over fueling and stuck the piston. Here is a video of what it sounded like,
http://www.youtube.com/watch?v=Hg7MiHwFDIw

I limped it back to the shop and had a complete in-frame rebuild and there was an obstruction in the #2 rod bearing oil passage so it spun the rod bearing and this is what it sounds like,
http://www.youtube.com/watch?v=9ks9T6cPxxI
http://www.youtube.com/watch?v=GVNLx0UsVzE&NR=1

The video is shaky because I'm about to cry after spending 13K on a complete rebuild and 400 miles later I was getting a tow truck ride back to the shop. The respectable company put in a new crank for at no charge.

With the piston knock I was able to drive it but with the rod knock there was no doubt I needed to shut the engine off right away before I had a big hole in the block . Since your able to still drive it's probably not in the bottom end. Hopefully these video will help.

Before you change your rod and crank bearings try using plastigage to check your clearances (you should check after installing new bearing too incase there not correct). It's really easy to use, you just take the cap off and put this thin strip of plastic in and put the cap back on. Re-torque the cap and take it off then you hold the smashed plastic to the package and it will tell you your tolerances.

Also while you have the pan off you can probably see up inside the cylinders to check for scuffed walls.

 

i would think that the oil pressure gauge is wrong for sure hook up a manual one they are very easy to install

 

Did you ever find out what happened to your truck?

 

I'd say definitely put an oil pressure guage on it first.

 

What's a good brand/model of oil pressure gauge/sender?