Wierd one but i'll do my best to describe...so I've towed the 5th wheel twice this spring so far and have encountered a new noise. When the truck is working (maintaining speed up a slight grade) a whining noise starts. It's a lower pitch but moves gradually to a higher pitch over the course of a few seconds and ultimately ends up in a high pitch squealing type noise. The squeal will last for another few seconds then disappear altogether. Process repeats itself each time the truck works a little bit going uphill. Also, the noise only presents itself at higher speeds...70 plus. On my way home the last time I kept the cruise on around 62-63 and the noise never happened. Seems like its different from the singing of the turbo.

5th wheel is approx 9,000 lbs loaded. Noise isn't present when unhooked and traveling to and from work.

 

Why on earth are you driving 70+ towing a 5th wheel that heavy?

 

just trying to diagnose the issue

 

LOL, internet speed cop...

Sounds like you have a boost leak. the early 05' trucks had plastic endtank CAC's. This would be my first guess if you haven't already replaced it or you have a metal one.

 

Got the metal boots, actually I replaced the plastic one about a year ago. I will go make sure the hoses are snug though

 

Woudn't that noise be the engine fan kicking in to pull more air through the radiator?

..

 

What you are describing is the fan clutch. My truck has the same symptoms - only when heavy load, hot and 2200+rpm

 

Texas, I was thinking along those lines as well. Wanted to get some ideas from you all who are a hell of a lot more knowledgable with these things than I am!

I do appreciate everyone's reply's!

 

Sounds like the fan clutch loading up to me to. Mine scared me the first time it did it going from a dead stop up over the intercoastal waterway in Gulf Shores in July's 105 weather, while pulling the 5th wheel. Once temps came back down it quit.

 

I had a similar noise, at higher boost pressures, when I had my '98 12v. It sounded like a really bad water pump. It was caused by a loose v-clamp, the one that connects the turbo to the intercooler tube. I tightened it and the noise stopped. It worked for me. John

 

I think the only time my fan has ever come on was when towing uphill with my fiver. When it kicked in, it wasn't a whine. It was more like a helicopter was flying over me.