What's up everybody!

First of all I just want to thank everyone who helped me when my truck started having transmission issues about 2 months ago (by the way, I realized I was way over my head and saved the money and took it to a local and well respected tranny shop and solved the problem). Anyways....

Here is my current issue. A little background first - me, my dad, and brother decided to undertake a project last November. We had a 1999 Dodge 318 (5.2) motor/tranny and a 1997 truck with a blown motor and tranny. We thought it would be a snap to put the '99 motor and tranny in the '97 body and call it a day. After all the grunt work, we realized that there were significant differences between the two years; especially with the transmissions and wiring. Well, we bull-headedly went forward with our project and got the thing running. In fact it has runs pretty well....

However, pretty much since we have been driving it regularly (January 2010), we have noticed a knocking noise. It is primarily audible in the cab and barely audible outside. I assume this is because it may be an issue between the engine and transmission. The knocking noise also speeds up as I rev the engine and *******ly becomes inaudible when the RPM reaches higher levels. Also, might I mention a little history of the transplanted '99; it was in a roll over crash (@ 80k) before we put it into our '97.

My question is: what the heck is the knocking noise? Could it be the flex plate, oil pump, water pump, connecting rod, or something else???? Any help would be greatly appreciated.

 

Does it do it at idle? In Neutral? Does the noise vary with engine speed, or with road speed? If it isn't really audible outside, but is inside.... might be as easy as a linkage or some such rubbing on the body.

 

have you done your plenum gasket , or tune up ?

 

have you checked you exhaust flanges where the cat meets the manifolds? i had an audible knocking noise in the cab which increased with engine rmp but couldnt be heard outside the truck. it ended up being one of the collector flanges bolts rotting off.

 

use a piece of pipe about 2ft long and 1/2 to 1in diameter as a stethoscope. thin wall emt conduit or any pvc pipe will work. be careful of moving parts, but place one end against the motor first and then your ear to the pipe. its amazing what you can hear. work your way up and down and around the motor and find the place where its the loudest. then report back.

be careful of moving parts.

 

Thanks for the pipe idea, will try it tomorrow and report back!

 

Hello all!

I found out what the problem was. I am enclosing a photo. This little canister looking thing was causing all that "knocking" noise. It has two plastic lines - one going to the breather and another going to the evaporator canister beneath the truck. It also has an electrical connection. When I started the truck today, I waited for about 5 minutes and the knocking noise started. I looked under truck and found nothing. I looked under the hood and heard a faint knocking noise (the same noise that is easily heard in the cab !). I felt around and touched this "thing" and felt the knocking...this was it! I unplugged the electrical connection and the knocking noise stopped. Okay...so I found what was causing the knocking noise but have no idea what it is...the Haynes Manual says nothing about it. What is it? Why is it knocking?

 

Okay...so how in the world do you put photos on this forum???!

 

upload your pictures to a hosting site, like photobucket.
then paste the IMG code into the thread.

did it look like this. its the purge solenoid

 

I'm not positive but I think that may be what I believe is called a vapor canister purge valve.