I am fairly new to the diesel world. I have a 96 2500 A/T with 47,000 miles on it. I bought the truck with 40,000. I have noticed it has a whine noise during acceleration around 1-3/4 RPM. It is really not that bad, but it is noticeable. Any suggestions on what this could be? What steps can I take to find out what is making this noise? Any information would be appreciated. Thanks, John

 

Is it a whine or a whistle?

 

I guess you could better describe it as a whistle. It is not high pitched though.

 

I'm not sure what you mean at 1 3/4 rpm. What I am thinking though is what you are hearing is a boost leak somewhere near the turbo. Check all your boots to see if there is one loose. You should also check the one on the lower passenger side (by the intercooler) for abnormal wear from the inner fender.
Tom

 

I think he means around the 1300 or 1400 rpm range. There is definetely the turbo whistle (high pitched). You can check if the previous owner took the turbo silencer ring off. This will make the whistle more noticable. Take the air intake hose off of the turbo that comes from the air filter box. If you see a sheet metal thick flange covering most of the intake your ring is inplace.

I also have a whine (much different than the turbo) that hits in at about 1700 - 2000 rpms. It may be drive train connected. Try coasting at the same speed but with engine at idle to see if the sound is still there. Maybe bearings, transfer case of AT. Good luck.

Paul