Read title... that's what I hear every now and then (more often now that it's a bit colder out) while driving.

It seems to go away/quiet down when I let off of the gas pedal, and under a load, especially driving up a hill, it really is noticeable and is very, very loud.

I can't figure out which area (front, rear, pass. or driver' sides) of the truck it's coming from, as it's so loud in the cab.

I just put front u joints in, as well as replaced the drag link and tie rod ends.

Still has the factory automatic locking front hubs... 139,000 miles on the truck total.

It has a true Dana TTB 35 on the front (front housing has strengthening ribs on it) and 7.5" non limited slip rear axle.

In case you need to know this too, it rolls on 31" BFG's. I don't know if that's too much for the 7.5" or not, as the truck came with them already mounted...

I do recall reading about how the 8.8 is supposed to be stronger, but only in terms of the differential carrier bearings (side bearings) or something like that.

The clutch was done a year ago, but the slave is already being a problem. It does not release or engage the clutch consistently. Works fine in the morning, but after lots of driving, it'll get harder and harder to get it to go into gears/shift properly.

Anyone ever have a noise like this? Insights/experience would be helpful as to where to start looking for the problem.

 

Probably the serpentine belt tensioner is frozen up and not keeping the belt tight.

 

There's always one thing I forget to mention...

I just put a new tensioner, serp belt, and idler pulley on it about a month or so ago.

I checked the fluids (they never change in level/run dry and are where they should be, so that likely isn't the problem)

Doubt it's the serp belt or its related parts since they are new.


Also, when the truck is not moving, it does not make this noise. I can let it idle all day long and I won't hear it. Once it's rolling faster than say, 45 mph, the noise really becomes prominent.

 

What brand belt are you using? I would start by pullling the belt off and checking for bearing noise/play in all the pullies. I had a squealing noise and it ended up being the water pump.

 

Goodyear Gatorback...

I checked all of the pulleys/accessory drives/water pump when the belt was off and no play was present, and the pulleys turned smoothly.

I'll check that all again anyways to be sure.

 

Re-reading the OP I remembered having a rear u-joint did this. I couldn't tell exactly where the noise was coming from. Dropped the rear drive shaft and found the u-joint was dried out.
The noise echoed through the cab so it was hard to find.

 

That does sound like the problem...

I do recall one of my instructors stating that a dry u joint will make a chirping/squealing high pitch noise...

I'll post back here once I figure out what it is.

 

Is your truck a 1996 3 liter? Could be cam shaft sensor if that year uses it.