Yet another front differential post

First real post. Been lurking for a while. This is a great site. Sorry for the long post.

Looking for some affirmation. I think my front, driver side, differential bearing is toast. After hours of reviewing old posts, seems to be the most likely diagnosis. My only concern is the noise doesn’t go away when I lock it in 4H.

I have a totally stock ’07, Off Road, 4WD, V6, Auto, Access Cab, no lift, 79,500 miles.

I hear a humming noise that starts at about 40 mph, reaches a crescendo at 57 mph, quiets a little as you go faster but, doesn’t go away.

I ruled out the driveshafts:
1. Absolutely no play in any u-joints. I greased them at 60,000. Greased them again for good measure. No change in noise.
2. Center carrier bearing only has 1/8” play. Seal is cracking but, no leakage.

I ruled out tire/wheels:
1. Replaced tires a few years ago at 60,000 miles and never heard any noise.
2. Tires are wearing evenly. Balanced and rotated tires for good measure. No change in noise.

I ruled out engine/tran:
1. Noise cannot be generated with the vehicle parked.
2. Dropping into neutral. Noise stays the same.
3. Downshifting to rev engine to a higher rpm does not change noise. Noise is completely dependent on speed of the truck.

I ruled out wheel bearings:
1. Reading the posts, I drove the truck up to speed until I heard the noise, kept the speed constant into sharp curves (both left and right). Noise didn’t change.
2. Raised the truck. Spun the passenger side wheel. No noise. Grabbed the tire and tried to wiggle back and forth. Absolutely no play.
3. Spun the driver side tire, rumbling noise.
4. Spun the driver side tire with a stethoscope near the wheeling bearing side of the CV axle. No noise.
5. Spun the driver side tire with a stethoscope near the differential side of the CV axle. Rumbling noise.

The last thing I want to do is throw a bunch of money and time replacing stuff that’s not broken. However, this noise is driving me crazy. I’m shocked by this problem. I meticulously maintain my vehicles and usually only replace normal wear and tear stuff. I sold my ’90 Toyota 4X4 with 232,000 miles on it and everything still worked. Other than wear and tear, the only thing that failed was a water pump and a starter.
TIA

 

sounds like your on the right track. i just lifted my truck and am now noticing what im guessing to be the same problem

 

Yeah, I guess I should have posted to this other thread,

That thread is up to 52 pages, now. I followed the advice and ordered a bushing from ECGS. I'm pretty sure it's my differential, there's lots of play in the CV axle. When I solve my problem, I'll post again.

Probably a more common problem on lifted trucks because of the added stress on the axle but, happened on my truck at stock height.

 

wierd that putting in 4x4 doesn't make it go away. i will also be ordering the bushing lol

 

My nightmare came true. I replaced my differential bearing (re-used my CV axle) and it didn't fix my problem. The ECGS bushing definitely removed the slop in the CV axle but, absolutely no change in the noise I hear while driving.

The noise I hear at the differential with the mechanic's stethoscope is likely normal gear noise.

Please, read my OP. Where do I look next?

 

I've had tires start off quiet but with 5-10k wear start making quite a racket. Something you could try to further rule them out is do a short drive at sidewall max pressure; this tends to change the sound if the tread is the culprit.

Boy, this really is a tough cookie. In your video it almost sounds like flowmaster drone without the flowmaster.

 

I had the same problem on my 2007 4WD Taco at around 70k miles. I thought it was a rear wheel bearing from the sound (my hearing is getting worse with age.) Since I had the extended warranty I took it to the dealer and they put small microphones on the frame and took it for a test drive. Turns out it was driver side front wheel hub. It was replaced under warranty and it came to over $600.

 

OP, there are a couple of things I'm thinking:

1. My left front diff. side bearing was visibly shot at about 16K miles on a bone stock truck and I replaced it (actually both sides) with the ECGS bushings at about 20K miles. Mine never made any noise at all but was excessively sloppy on the left and the right side's needle bearing destroyed the stub shaft on that side.

2. Although the noise disappearing when 4WD is engaged is a major diagnostic clue it is not exclusive. As I said, mine never made any noise and several posters have now reported that the noise did not go away on theirs either when 4WD was engaged, but the needle bearing was bad.

3. 2nd gen. Tacomas are not known for their robust wheel bearings. You may have given up too early on ruling out the wheel bearings. At nearly 80k miles I don't think anyone would be shocked to find a bad wheel bearing. I found water in one of my front bearings when I did the ECGS bushing at 20K miles so I replaced both. The inner wheel bearing seal is a piece of junk and water can get in there easily from power washing and water crossings. The poster above me who referenced the "hub" probably means the wheel bearing module as the term is used very loosely.

4. There are other things that rotate up front that would change noise with speed such as the CV joints and other parts in the front diff. The right side of the front diff. has a ball bearing where the CV shaft feeds into it that is always rotating as well.

5. You might want to consider moving your post/thread to the other major one mentioned above. I know it a very long long thread now but a number of the veterans who dealt with this problem still monitor that thread and you might get more constructive feedback.

 

Excellent idea. I tried but, no change in sound. Makes tires less likely.

ECGS took out lots of slop in the driver CV axle. So, like you said might have been a bad needle bearing. Unfortunately it didn't fix my noise. I too am wondering about wheel bearings but, I can't hear any grinding even with a mechanic's stethoscope.

I found a post that said to drive the truck and then check for excessive heat near the wheel bearing. Nothing there but, got me thinking about trying the same thing with U-joints. I drove my truck over a hundred miles today. When I got home, I checked all my u-joints and found only one that was hot to the touch and only on one side of the same u-joint. That's odd. I think I may just swap that u-joint and see if that fixes my problem.

What's frustrating is I've had u-joints and wheel bearings go out on my older collector cars and it's alway so obvious. Major slop in the u-joint or grinding/growling noise in a wheel bearing. I've had my truck on jack stands dozens of times and I've yet to find anything obvious, other than the loose CV axle that I already fixed with the ECGS bushing.

I'll take your suggestion, also and try posting in the other thread.

 

^^^ Hmm. A single hot side on a single U-joint. Why not take the rear drive shaft off (index mark both sides first), engage 4Hi and drive around using only the front drive shaft. It won't hurt anything. See if the noise changes.

 

I thought it was the bearing in front diff because u-joints seems to be fine. I even greased them.

So, I decided to give it a try, I changed two u-joint in drive shaft and they were toasts, even there were no play ... Inside rollers were missing in two u-joint.

So, before going in front diff bearing change, try to change you u-joint. They aren't costly.

 

Sounds like the joint is the source of your noise issues, but If changing the u joint doesn't fix the noise issue, you might have some damage internally in the diff due to the cv axle putting excessive strain on the spider gear assembly inside the diff. Check your diff oil for sure, my first taco had this noise issue and when I drained the oil there was a MASSIVE amount of metal filings in there due to excessive gear wear...

 

I drained the front differential when I replaced the differential bearing. No metal fragments whatsoever. Fluid was clean.

I replaced my u-joint and still have the noise. I knew before I finished the job. When I removed and inspected the old u-joint, there was absolutely nothing wrong with it.

I'm running out of ideas. Wheel bearings next???