Hello everyone, I just got back to WI from FL - pulled 2 cars back in an enclosed trailer. Last night when I arrived home I had the truck idling and noticed a weird engine sound coming from the engine, specifically the passenger side of the truck by the front tire. Sounds like the exhaust pipe is right by the right front tire - when I rev it up it gets louder. I did not notice any increase in noise while driving. Engine idling sound seems normal. I have my exhaust manifold wrapped in exhaust tape so maybe I have a crack under the wrapping. I am HOPING that is what the noise is. If I can not figure it out, do you suggest taking to a dodge dealer or straight to a cummins dealer? Any thoughts on what it could be? Makes me nervous.

I know it is tough for someone to give advice based on a verbal description vs acutally hearing it.

 

Quick question - from my understanding the manifolds the 3rd gens can crack. If they do, where specifically on the manifold will the crack occur? Thanks
Scott

 

If you have an exhaust leak, you'll eventually see soot around the area, which will help you pinpoint the leak. If it was me, I'd remove the wrap and look for signs of soot. when installed my new turbo (@90k miles ago), I didn't tighten one of the exhaust connectors, and it had soot around that area within a few weeks. It was only a slight leak, because it didn't make any noise.

 

Also, activate the EB, if you have one, or restrict the exhaust (at idle) to help find a possible leak.

 

Thanks - From my understanding the 2004.5's do not have exhaust brakes.

I do put the truck into the tow / haul mode when going down steep hills, tends to help maintain the truck's speed and save the brakes.

I do not know if this is hard on the tranny or not, I would not think so, like a reverse of the torque applied to the trans under load.

 

I am only suggesting that some back pressure in the exhaust may assist you in trouble-shooting an exhaust leak. Also, it may help to remove the Cat and check it for loose pieces inside.

 

Thanks for the reply

No cat on the truck

 

Hello everyone - the exhaust manifold does not seem to be cracked. I did find clues which leads the issue to a different area. The noise sounds like valve train noise to me. Here is what is weird - the truck returns to the idle noise I am used to if I put the truck in reverse It makes the "noisy valve train" noise in Park, neutral, and drive. When I drive the truck slowly and let off the throttle, I hear a grind noise or like a rough caugh noise.

So what would cause the noise to go away in Reverse? I assume the noise is coming from the tranny.

I did check the level of fluid and seems to be fine, color is seems fine as well.

 

Check the fill tube on the transmission Sometimes it will vibrate and make that type of noise. Use a large plastic tie and secure it to the external trans cooler pipe that runs next to it.

 

Ok - I will try that. I did notice when I was checking the fluid that the fill tube was moving / vibrating quite a bit.

Hopefully that is it

 

Hello everyone, while backing up my trailer I was shocked to hear the noise go AWAY! The noise occurs in Park, Neutral, and all the drives but does not occur in reverse.

Very Weird - sounds like a valve train / rattling / noisy diesel noise. Truck gets really quiet / goes back to the sound I am used to when I put the truck in reverse. Very repeatable

Any ideas or suggestions?

I also hear a slightly louder noise right after I stop driving forward when going very slow. Noise is only for a brief moment.

Trans fluid looks good as well as engine oil.

I look forward to your suggestions as to what it could be. I did call a local trans shop and he did not know what it could be.
Scott

 

Check crankshaft end play, if excessive the torque converter bolts could hit housing when crankshaft moves forward. Usually happens when doing a quick stop when moving forward. This is not common problem but I have seen this condition a few times. Could also be a cracked flex plate, this noise usually goes away when load it placed on engine then comes back when there is no load.

 

Hello everyone,

I had a friend come over and help me try to find the noise. I was hoping to see a bad motor mount / bad tranny mount but the set up it rock solid, very little movement. I took the inspection cover off and I am 92% sure that the sound is coming from the bell housing. I am thinking that I have a cracked flex plate and for whatever reason, it gets quiet in reverse. It also seems to get quiet when I drive and get's noisey when I let off / come to stop.

If it is a cracked flex plate, my thought is to replace the flex plate and torque convertor. The truck has 180K - mostly highway miles. I intend on keeping the truck another 4 years which means maybe 50K miles. Do I spin the wheel and redo the tranny or hold off? How does one know whether or not to spend the $2800 to $4300 to rebuild the tranny?