Rear end howl at all speeds

[greif07]

Appreciative of any input. I have a loud howling that starts in the rear end from low speed at take off and sustains the whole time the truck is moving. It only changes in volume and slightly lowers at higher speeds. Sounds like hard mud tires or a prop plane if you had ear protection on. Around 40mph and up I also get a high pitched kind of whine. It sounds like a wheel bearing but the wheel feels ok (no play), it doesn't change tone when shifting weight/turning left or right or when changing surfaces (pavement/concrete). I noticed low volume noise that sounded like tires for a little but, but this seemed to happen suddenly. I got in it 2 days ago and the noise was much more apparent. One of those 'what the hell just happened' moments.
I just changed the u joints in the rear driveshaft due to some play and lubed the drive shaft properly. Nothing changed there except the driveshaft clunk.
My tires do need to be replaced, but can't imagine tires being that loud and getting quieter at higher speed or sounding the same over concrete.
There's NO vibration or anything else that feels weird. It drives perfectly fine except for the noise.
Also, it doesn't change if I go into neutral at any speed or in 4wd. It does sound to be coming from the RR corner but that may also be biased from the driver's seat. I'm a pretty capable diy'er, but I don't have a press or capable tools for wheel bearing and looking to get some input before I send it to the dealer. I don't see any leakage around the axle but i do see signs of previous splatter above the input of the rear diff.
I traded my newer, lower mileage BMW that I did all work on for the 3rd gen. I don't know the local shops that well because I did all my work and had a BMW tech available for major stuff. I just don't want a shop throwing parts at it. I'm going to try changing the driveline fluids and see if that changes anything, but I'm skeptical of any fluids being magic.
Thanks again for any input.

Forgot...it's a 98 Limited 203k.

 

[4Running Daily]

Don't quote me on this, but if I were to guess, I'd say Diff bearing.

 

[greif07]

Thanks for the quick response. Would there be any play in the diff input shaft? I did check it for play when I had the drive shaft out and didn't notice any. I turned the drive shaft by hand before I dropped it and it wasn't 'smooth' per se. Hard to describe but felt like rough spots somewhere.

 

[downpour11]

Don't quote me on this, but if I were to guess, I'd say Diff bearing.

That would be my guess too. Didn't that recently happen to COB? lemme find the link with the video...

 

[greif07]

If the diff bearing is bad, would I be better off finding an axle than repairing?

 

[downpour11]

IF it's your pinion bearing, prob just replace the whole 3rd. Search "pinion bearing": http://www.toyota-4runner.org/3rd-gen-t4rs/74819-2000-4r-whining-howling-pinion-bearing.html

I'd start there and see if it sounds similar to your problem. Could also be a wheel bearing.. Just a couple thoughts. Hopefully someone with more knowledge can chime in.

 

[greif07]

Unfortunately I have to drive the truck about 40 miles round trip.. I shouldn't expect any catastrophe...right....???!?

 

[Dous]

Unfortunately I have to drive the truck about 40 miles round trip.. I shouldn't expect any catastrophe...right....???!?

If that bearing were to lock up and start spinning the race you would ruin the 3rd member. It could also disintegrate and cause a bunch of metal to float around in the diff and ruin something else. But it would be really loud before that happened, my rear end has been howling for the past 10k miles and I don't worry about it....although I do work at a gear shop!

 

[Monkeybutt2000]

Wow, was just at a buddies yesterday and his 4R is doing the exact same thing. He changed the diff fluid and lubed the driveshaft but the noise was still there. I told him it had to be one of three things. Carrier bearings,wheel bearings or pinion bearing,just don't know which one!

 

[greif07]

Yeah it sucks. I've had the truck for less than 2 weeks but sought out a 4R on purpose because I know in general they're reliable. My sister bought a new one in '02 for $40k (ouch) and it treated her well over the years. This one started with the howling a week after I got it.. :ak472:

 

[SamSter0077]

Had the exact same complaint once before after replacing the r&p after grinding the teeth off the old one. Turned out it was the pinion bearing, mine was loudest on deceleration. The pinion was moving around, the bearing was toast.

Seems like if you remove your rear driveshaft and drive in front wheel drive... If the sound changes/goes away. it's the diff...maybe that only works with vibes..

 

[greif07]

I'm leaning more toward wheel bearing. It's sounds more biased to the right rear side and there's no tone or volume change if I let off the gas. It does sound similar to the roar in my cars wheel bearing. That howl also started at low speed and sustained. Didn't change with side-to-side load either.

 

[Goldrush]

95% sure that would be a pinion bearing seeing as how it increases as your acceleration increases. purchase a new setup kit. The pinion would move a bit as well. The noise i would pretty much guarantee that it is in the diff

 

[jspagna1]

Ya it's your rear end gears. Bought my 97 brand new and now my 17 year old daughter drives it back and forth to high school. Figure when it craps out, I'll deal with it and get it replaced.

 

[greif07]

I got underneath it today and there's some play in the output flange of the transfer case. I heard a clunk over a bump and got under then bounced it up/down. I saw the output flange move and that's where the clunk is coming from. I know that's bad but would that sound like a howl from the rear end?

 

[greif07]

Dropped the rear driveshaft down today and changed the rear pinion seal while I was at it. There was absolutely no play in the pinion at all. Added fresh Lucas oil and still sounds the same. It's getting dropped off tonight at local shop so ill see what they have to say.

 

[Bt08231]

It's the pinion bearing, I have a 98 with 198k and it does the same thing. Toyota tech at dealer said it will not " catastrophically" fail and will be loud as hell before anything happens. His recommendation was to drive it as is until it was too annoying then replace with a junkyard unit. It's normal

 

[greif07]

It's been to in the shop and diagnosed with bad pinion bearing. I got lucky (I hope) and found a complete axle locally for 350. It's being swapped at the garage now and hopefully back tomorrow.

 

[greif07]

Just got the truck back after the complete rear axle was swapped. I've never heard the truck this quiet. Seeing how I had the whole thing replaced, I can't say 100% that it was just the pinion bearing causing issues, but it's probably 99%. The shop ended up having to strip the old axle (it was cut off the donor vehicle) and I also got some new shocks while they were at it. My truck and the donor are upstate NY vehicles so the hardware wasn't pretty. I guess it took a lot of heat to get both apart. Anyway, I'm surprised that my bill was $580 because I was sure it would be more. No more prop plane takeoff!
Thanks for all your input.

 

[andes]

Sounds like my problem...

Reply to Greif07

I never have added or changed out the differential in front or rear, but after a tire rotation and brake job, I got the howl sound that was 2 months ago.

I have eliminated the diff. fluid as the problem.
I believe it to be my bearings, specifically the pinion, now I will seek confirmation and try and find the complete axle like you.

I need to put this thing to bed, without going to the stealership.