Ok. I left work engine wasquiet on start up. By time I got home (about a 30 minute drive) I heard lots of knocking. I changed the oil and found no shavings or even fine particles. When I started it after oil change it was quiet for about a minute then slowly started again. At higher speeds it stopped but at lower speeds you here it. I'm thinking rod bearings. Any other suggestions.

 

well it could be a number of things.... first things first, do you have an automatic or standard transmission?

 

Automatic. 4.0

 

I thought I had a lower end knock once before and fortunately for me it turned out to be the water pump was bad. Get yourself a stethescope and poke around and listen to the engine.

 

used a stethescope and poked around. seems like most of the noise is coming from the rear of the engine. when i put it on the oil pan i get the loudest noise.