Grinding/roaring noise between 10-20 mph

I have a grinding/roaring rotational noise between 10-20mph. It sounds to be coming from the rear of the truck. I took it to Toyota today and they said it was the rear diff but all they did was drive it. They did not check fluids or anything. I have not been good about servicing the diffs and it has been quite a while since it was changed. Not sure the mileage of last change. The truck has 226,000 miles on it. The carrier bearing is for sure bad. I changed the fluid in the rear diff and there was barely any metal flake in the fluid and just a little build up of it on the plug. I stuck a magnet in the diff and did not pull out any metal shavings or chunks either. The fluid was in no shape or form silver like I have seen in some of the pics on here. I rode in the back of the truck and listened and can't really pinpoint where it is coming from but it is loud. It has also been a while since I did the rear brakes. Has anyone had this type of noise and not have any signs of diff failure in the fluid but still have to replace the diff or could that carrier bearing be that loud? The noise happens in gear or not and I am sure is still happening at high speeds but can not be heard due to the speed of rotation. I am about to go on 14 hour trip and concerned the diff will fail based on what Toyota said. I do not have time to get things in order before the trip but really needed 4x4 on the trip that our other tow vehicle does not have.

 

Can you post a video of the sound ?
What do you mean you can hear the noise in gear and when its not in gear ?
Are you placing the shifter in neutral and coasting ?
You could always pull the rear driveshaft off , put the transfer case in 4x4 and test drive for diagnostics

 

I am putting it in neutral and coasting and the noise is still there. Also hitting the brakes does not affect the noise. Let me see if I can get a video.

 

Ok I went out and tested again on a smooth quiet road, there is a difference in gear and in neutral coasting. The noise gets much quieter while in neutral. It does not go away but is probably 3/4 less loud.

 

Without a little video , its tough for members over a keyboard to diagnose sounds .
My suggestion would be to put the truck on a hoist before you leave on your trip and start probing with a stethescope as the driveshaft and wheels are turning .
You will have to have someone in the truck as the noise is more noticeable under some load
If something is coming apart , a stethescope will find it and possibly save you some greif down the road .

 

Upload your video to YouTube and then post the link here.

 

https://youtu.be/5LaQeZz8kME

Here you go

 

I didnt hear anything in 14 seconds of video.

 

Also to note this is a new set of tires and it was happening with the old set too. It almost sounds like metal scraping

 

I can hear the noise in the video but I guess it is because I know what to listen for. It is really loud in the truck.

 

Understood.
The carrier bearing, the u joints and the part that the drive shaft hooks to on the third member (the name eludes me currently), rear brake drag, or gears in the third member housing.
These are the guesses, put it up on jack stands and have a go at starting it and spinning the tires to pin point the sounds

 

I'm guessing the unknown is the pinion gear? Wouldn't any failure in the third member show up in the diff oil? How would you adjust rear brake drag? I know the carrier bearing is bad but I don't feel like it would make this much noise. I do not feel any vibration anywhere either.

 

The diff oil definitely needs drained and refilled. I suppose it could be a rear wheel bearing too.
The pinion gear and seal..is the seal leaking, when were the last time the u joints were greased? Do they have zero fittings to grease them?

 

I just replaced the diff oil. There was a little bit of metal flake on the plug but not much. I checked inside it with a magnet and did not pull anything out. I also ran my hand around in the drained oil and found no metal shavings. The ujoints were greased recently or were supposed to have been when I got my last oil change a week ago, I'll check that. No leaks from the pinion or the wheel bearings on either side. The rear brakes are due to be changed. There is no leaking or sign of a wheel bearing failure on the rear or either side but I guess that could be it. Toyota said the rear diff but like I said they just drove it and then wanted 2200 dollars to replace it, never even put it on the rack. I will temp check the axel tomorrow when I get to work and see if anything seems excessive. I just dont want this thing to explode on me before I can get it changed out. I have the carrier bearing and will change that out next weekend and will probably go ahead and do the front and rear brakes.

 

If anyone was wondering what happened. I pulled the drive shaft today and replaced the carrier bearing, and all the u joints. One of the u joints was bad as well so I figured I would go ahead and replace them all. While inhad the drive shaft off i put the truck in 4 hi and did a test drive. The sound was completely gone, the truck was stealth bomber quiet. After putting the shaft back on the sound is back. I am pretty sure it is the pinion bearing and taking the weight off of it by removing the drive shaft silenced it. All that being said does anyone know the best place to get a bearing kit for the rear diff? I figured if I'm going to tear into the diff I might as well replace them all. If I get in and the whole diff is bad I will just order a used elocker diff and put that in.

 

I have the exact same problem. I've changed out front wheel bearings, checked the U-joints and they are ok, so I'm assuming either carrier bearing or rear wheel bearings (my mechanic does not think the rear wheel bearings are the issue).

 

I tore mine all the way down, I pulled the rear diff and and axle shafts. One of the wheel bearings was toast but it did not make noise when the drive shaft was on which was weird, must have been when it was under load. The upper pinion bearing also had some pitting and the carrier bearings had wear that you could feel. I think now most of the noise was in the rear wheel bearing but the bearing in the diff need to be changed to so I am just rebuilding the whole rear axle. As a matter of fact I am doing the axle, rear brake shoes, all 4 shocks, rear springs I got from the recall and a front cv axle while it is down for the count. I bought the bearing removal tool to do the rear bearings if you are by any chance in north alabama I'd rent it to you for 20 bucks if you wanted or we could work out some sort of deal with it if you wanted to use it when I am done, (ship it to you and you return it if the cost was not too bad). I'll let you know how it goes.

 

Was it the rear bearing? I have noise at 15mph. I jacked the rear up and had it steady at 15mph and there's no noise or vibration. I've replaced both front hubs, did the clamshell bushing and installed a one piece driveshaft and the howl at 15-20 is still there.