I have a 2000 dodge dakota 4x4 with 4.7 ltr engine 123,000 miles. No codes and operates very well...
I have recently had the tranny rebuilt <1000 miles ago and replaced the Fan clutch. Before and after the above repairs I have had a persistent and annoying sound which starts at start up for about 60 seconds then goes away. After about 20-30 minutes of driving this sound returns. The sound resembles a high RPM sound but the engine does not indicate high RPMs. After shifting through the gear the AT RPMs drop to between 1500 -2000 and the sound goes away only to return after stopping and accelarating again. :confused:I changed the fan clutch as I was told by the "experts" at our local Dodge dealership that this is that cause of that sound. Any Ideas? BTW I live in Florida and running without the fan clutch and relying on just the electric fan is not recommended. Thank you.:)

It sounds like the fan clutch. I have a 2000 Dakota, 4.7, 5 speed. I know driving around in the northeast isn't as bad as being in Florida temperature wise but every once in a while my fan does just as you described. Since I seldom hear it is usually surprises me a bit.

It may do it for a minute or so at start and sometimes while driving around, usually in stop and go traffic.

Check to make sure your radiator/condenser are clear of bugs. You want as much air as you can in there.

You may also need to get your radiator flushed, especially if it hasn't been done before. Watch your temperature gauge when it occurs.

It is very possible that the part that was installed is faulty.
I've been around cars long enough to know that "new"is an acronym for "never ever worked."
Check your part's warranty and inquire where you bought the part if they have problems and what they recommend.
Let us know what happens.