Differential hum..

J

jonesmw10

New member
Hey all. It sounds like I have a hum coming from the rear diff on my 08 V6 4x4. I noticed after changing the fluid and it has progressively gotten worse (i used the correct fluid, old fluid was nasty). The noise occurs only slightly under hard acceleration and is very noticeable at 55 mph when his coasting and losing speed. As soon as you give it a bit of gas when I can hear it, it stops. I'm thinking a pinion bearing.. Any input? All help is appreciated!
 
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Noises in video are always hard to distinguish for me? I heard what sounded like a semi-truck passing you twice during the video. Is that the sound that you are talking about? Sort of a high pitched whine?
 
Resurrecting my super old thread! Issue still exists to this day and a few mechanics found no issues. In the past week, I have started to feel vibrations.... Or grinding? through the floor at certain speeds. The hum hum hum noise gets louder when turning right but no worse when turning left (at high speeds it's very noticeable). I'm thinking a bad wheel bearing? Just finding it hard to believe that it's taken a year to show more symptoms.
 
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I have a 06 V8 RWD Sport Edition and when I changed my diff oil I did notice the humming noise (might be coincidental) and same condition as you mentioned. As each day progressed, it got worst..turned out..had to replaced the differential assembly..$1200 poorer
 
Same thing recently happened to me. Pulled the rear diff and found 4 teeth on the ring broken. This was not due to abuse! If you're adept, I would suggest pulling out the 3rd and seeing what may be going on in there (or if you have a lighted scope through the fill & drain holes).

Noise started the same under certain throttle / coast situations (mostly around 55 MPH). Lasted awhile like this and then very quickly progressed a sound similar to a bearing going bad.
 
I replaced my 3rd with an ECGS unit a few months ago. It was pretty easy. Total cost was around $700 and includes a 5 year warranty.

I'd investigate the wheel bearing until you've ruled it out, however. The wheel bearings have a worse track record of going bad than the differentials although either could happen. If it gets worse while turning I'd suspect the bearings before the differential.
 
I'm on my 3rd rear diff, in 95k miles, seems like these things have wimpy rear diffs for whatever reason as I found MANY threads about cooked 3rd members when I was searching around last year. At least, more 4th gens appear to suffer from this than other gens, IIRC they beefed up the diffs a bit for the 5th gen.

In any case, mine was indeed the 3rd member, at the beginning stages of the problem it was a small whine only under load/certain conditions, then it progressed to be what you're experiencing. I went through the wheel bearings as well at first as it sounded logical, but no dice for me.
 
fdbyrne said:
I replaced my 3rd with an ECGS unit a few months ago. It was pretty easy. Total cost was around $700 and includes a 5 year warranty.

I'd investigate the wheel bearing until you've ruled it out, however. The wheel bearings have a worse track record of going bad than the differentials although either could happen. If it gets worse while turning I'd suspect the bearings before the differential.
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For the record, I don't actually think that it was the differential that was bad. Replacing it didn't help me but I'd already done the bearings and nothing else made sense. I'm pretty sure that mine ended up being the tires. It's hard to admit that I'm the sort of idiot that could mistake tire noise for something more serious but those new, but extremely crappy BFG Rugged Terrains made so much noise and rode so rough that I assumed something else had to have been wrong. They were new tires after all.

This won't be the case for most people, but it's a good cautionary tale about throwing money at noises and vibrations. Get it diagnosed by a pro even if you plan on doing the work yourself. The small amount of money for a definitive diagnosis is worth a lot. You won't change out parts unnecessarily.
 
Tire noise doesn't generally change as you get on and off the accelerator. Gear noise does. That's the key way to tell the difference.

Bearing noise will usually change as you corner. Again, tire noise usually remains constant under those conditions.

Tire noise changes most with changing road surfaces.
 
RonJR said:
Tire noise doesn't generally change as you get on and off the accelerator. Gear noise does. That's the key way to tell the difference.

Bearing noise will usually change as you corner. Again, tire noise usually remains constant under those conditions.

Tire noise changes most with changing road surfaces.
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I think you misunderstood my point. I wasn't suggesting that it was tire noise. I was using my experience as an example of why it's better to pay a local expert to diagnose the problem for sure rather than guess or take the word of a bunch of Internet guys that only have a sound recording to go off of.
 
Sorry, I wasn't trying to be critical of you, and I certainly didn't think you were suggesting it was tire noise. I was just trying to offer the OP some ideas so he could better figure out the source of the noise, not us. I agree it's pretty hard to diagnose from a recording.
 
Looks like I finally have an update. I heard the noise this morning while I was warming the Runner up (not moving). Appears it is actually the exhaust. Can't say I was expecting that one.
 
Help with drivetrain noise(normal or not)

I am too young on the site to start my own topic but need input from other drivers.

I have a new to me 2006 4runner V8 4wd with 37k miles. It has a full log of records including diff and transfer case fluid changes from toyota. When I get over approx 10mph you can hear a noise toward the back of the car. It sounds almost like wind noise but I'm concerned it may be the drivetrain? I'm curious if this is just normal or I may have an issue in the future?

It is not tires, wheel bearings, pinion bearing, or fluid. It does get a little louder with speed but does not change pitch or go away in neutral or pushing on the brakes.
 
replace the rear diff gear oil and see if it changes if so then the diff has some wear issues. this can be from being poorly made or the use ofthe wrong gear oil.. also the rear diff if it is making noise is usually from hard driving of the vehicle the first 500 miles.. also diff gear oil changing should be done at the first oil change if the gear oil is dark or black / smells bad..
 
Hiker865 said:
I am too young on the site to start my own topic but need input from other drivers.

I have a new to me 2006 4runner V8 4wd with 37k miles. It has a full log of records including diff and transfer case fluid changes from toyota. When I get over approx 10mph you can hear a noise toward the back of the car. It sounds almost like wind noise but I'm concerned it may be the drivetrain? I'm curious if this is just normal or I may have an issue in the future?

It is not tires, wheel bearings, pinion bearing, or fluid. It does get a little louder with speed but does not change pitch or go away in neutral or pushing on the brakes.
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[MENTION=167870]Hiker865[/MENTION]
See if the rear crossbar on the roof is loose. I kid you not, I had a noise from the rear over 10. mph. Was the crossbar vibrating. Fixed with some soda bottle shims and rtv.

Nice when it's a cheap fix.
 
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