Only when you are accelerating? Will it howl just normal constant speed driving as well? Do you have automatic locking hubs?

 

It is loudest around 35-45,but it does it at all speeds,I am doing a tranny flush right now and replacing the filter to see if that helps at all,and no,i have manual locking hubs,i never converted over to automatic because i was told the vacuum seals or whatever go bad a lot so i stuck with manual.

 

oops and i wouldnt say just accelerating,i can just barely press the gas and it will make the noise

 

One thing you can do is put the hubs in free and see if that does anything or not? Does the truck have a carrier bearing at all for the rear driveshaft? I just had the same issue your having. And I changed mine. No more problem. Hope this helps.

 

Keep in mind that putting the hubs in free does not necessarily mean they are disengaged. They can stick in either free or engaged, regardless of what you put it to. The only way to be sure is to jack up the front wheels and spin them and see if they are free.

 

Yeah that's true. When I check mine I reach in and see if f I can spin the axle by hand just to make sure. I should have said that but forgot lol

 

From your first post, it is not clear to me if this issue goes away with the hubs engaged, not engaged, or not related. If unrelated, could it be the turbo rubbing?

 

yes the carrier bearing & driveshaft have both been replaced/balanced twice when i first bought the truck and it makes the noise even when hubs are engaged,but i havent checked yet to see if there truly disengaged or not,i will do that today.I did a tranny flush yesterday,did not make a difference at all.thanks for the help guys

 

....and even if the hubs were sticking and not disengaging,wouldnt it make noise whether i am on the gas or not because as soon as i let go of the gas it stops

 

turbo whistle?

 

Rear axle?

 

I experience a "howling/whining" noise when I am accelerating hard also but it is only when my Wife rides with me!:evil

 

My thinking is either rear axle or transfer case. The howling under any load is an indication of bearing getting loose and allowing the carrier to "tweak" causing the noise you are experiencing. Is there adequate fluid in both the rear axle and the transfer case?

 

I had this happen to me 10yrs ago, it sounded like a bad power steering pump or a transmission issue, i did 2 trans flushes ect ect. It turns out that I had cracked and chipped turbo exhaust blades. I abused my turbo.
Pull off your downpipe and look inside the turbo with a light and look closely you may see hairline cracks and I would be willing to bet a piece of one or more of the blades are damaged.

 

Im in this same boat rite now I believe, kinda sounds like a howling/ blowing over a beer bottle noise??

 

I have been having the exact same thing with my 07 for a while now. I'm thinking either carrier bearing or rear end. I hope it's not the rear end. Stupid question but, are these trucks posi traction on the rear? I've noticed that when getting on it, only one tire is spinning.

 

My 2000 ford excursion makes a slight howling/whining sound. It does it when I accelerate, and stops when I let off the gas. I can make the sound come and go by touching the gas, letting go, touching the gas, letting go, etc........ In neutral, I can rev the engine as much as I want and it does NOT make the noise. Putting it in reverse-it does NOT make any noise. I have replaced the idler pulley, belt tension pulley and serpentine belt but this made no difference. My transmission has been completely flushed and a new tranny filter installed. No difference. The truck shifts fine. No slippage, no delay...it shifts beautifully.
Also, rolling down the road at any speed, put it in neutral and coast, NO Noise. Any help out there?????

 

Check ur ujoints sounds like u have one going bad. I have seen plenty that will sound just like what u are describing.

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mine was making a howling sound for a couple of years. i finally figured out what it was 3 weeks ago pulling my snowmobile trailer back from a 650 mile round trip. my pinion bearing went out. had my whole rear diff rebuilt, no more howl

 

all u-joints and driveshaft have been replaced - that was a separate problem - blue glide coat at splined connection deteriorated - there is no carrier bearing with this configuration

 

Thanks! I was half suspecting the pinion bearing, but did not want to mention it and put the idea in everyone's head - i was waiting for someone to bring it up.
7 years ago my pinion seal was leaking so I replaced it. The backlash adjustment on the bearing is tricky. I have been suspecting that I did not get the backlash correct, or that the bearing was also damaged at that time due to low lubricant - although the howling/whining noise did not start until 3 years ago. Was it the outer pinion bearing (I can do that one myself-still have to get the backlash correct) or the inner pinion bearing(I would have to let someone else do that). Sounds like you had the whole unit rebuilt, so maybe you can't answer that question. Unless someone else can come up with a plausible cause, I guess I will be replacing the outer pinion bearing this spring. Thanks to all!

 

Mine was the inner bearing that goes on the pinion gear. I did exactly as you did. Probably 4 years ago I replaced a cracked yoke on my rearend. I just used an impact to put the pinion but back on. Wasn't aware of the crush sleeve. That's what wrecked the bearing. It took a couple years, and alot of chasing before it finally went.

 

You could pull the rear driveshaft and both rear axles (plug tubes with rag) out and take it for a ride in 4wd. The gears won't turn, noise should go away. I always thought about doing that but never did.