So I have had an eventful past 2 months. In that time frame I have replaced the transfer case, overdrive housing, front and rear driveshaft and the radiator fan clutch. I recently drove cross country from North Dakota to Oklahoma, and about halfway through there was a faint sound that I didn't notice until my cruise control started hitting higher RPMs going over hills. When the engine is in idle, the sound is not audible. I can put the truck in drive, neutral, reverse, hold the brakes down and rev the engine and it cannot be heard. The second I start moving and hit 2k RPMs, there is a screech almost like tires that don't have traction are trying to drive, and then the sound goes away after shifting. It's not audible, or seemingly present, until after 2k RPMs, and the pitch increases and gets louder as the RPMs increase. I have replaced the belt, idler pulley, and tensioner pulley in caution and the sound hasn't changed at all. Does anyone have any sort of idea as to what to could be? To my knowledge, it is not the bearings or brakes or anything revolving around the drivetrain. The bearings were replaced around 10k miles ago and the brakes were done around the same time. The transmission had a complete overhaul 15k miles ago, so unless it died that fast I don't see that being the problem. There is no jolting, or bumping or grinding. I've never heard of it before and can't find a single thing online where someone didn't find the solution with any of the parts I've replaced. Thank you in advance

 

Is the vacuum to your 4x4 damaged and allowed the collar to partially touch shaft?

bearings can be bad with no play, spin tire and grab coil while it’s rotating, the bearing will vibrate through the spring.

i work on vehicles for a living and I’ve seen new wheel bearings go bad in less than 10k many times…

fluids all up to par?

loose lugnuts?

or try taking belt off and try to duplicate it to eliminate pulleys

also have you checked pinion bearings

 

Is this a 2WD or 4? You didn't say anything about the u joints. Even if the brakes were done 10 k ago doesn't mean they couldn't be making the noise.

 

he did say front and rear driveshaft has been replaced

 

​​​​​I have a Posi-lock electric unit for the CAD, so the vacuum line for that isn't necessary. Fluids are all up to par, recently did an oil change after the transfer case was put on, all less than 1.5k miles. I didn't think about lugnuts, I'll check those here in a few minutes and get back to you on that. I was thinking it could be the pinion bearings, or any of the bearings up front for that matter, but the sound seems to high pitch compared to everything else I've heard. I'll try and grab a small video so that you can hear it for yourself if my phone would like to pick up the sound.

 

There are two u joints by the wheels in a 4wd that go out before the drive shaft ones.

 

So I was able to find the issue. It turns out that 2 of the wires in the steering column had rubbed together and corroded, so I resoldered them and put some hear shrink on them. But I have since run into one more issue. I was driving earlier tonight and had no issue. I got home, ran is inside for dinner and went to go out with some buddies. I turn the truck on, go to turn the headlights on, and they work. But my dash lights don't come on. I checked more, and here's what I have. All electricals are fine. I have no blown fuses in the cab or under the hood, I have power to the interior dome lights, my dash lights, radio, power lock and windows. I have no turn signal, running lights (the amber lights that you can turn on before headlights), no hazard lights, no taillights, and no dash/instrument cluster lights. Its pitch black out and I'm not willing to sit out there in the dark and cold trying to see if I can find a wire somewhere that might've corroded, but is there anything anyone can suggest? The dimmer switch works fine for the interior lights, and there is no burning on the switch.

 

Download the service manual for your truck from here. Wiring diagrams are in section 8W. Find out what the failing circuits have in common, and you will likely find your problem. Gotta be something fairly simple for them all to fail at once.