Rear Rotational Noise...ideas and help?

[mchestnut]

Hey team -

Working on a brain teaser over here, and need a driveline/train 'whisperer' to give me some advice/insights.

Here's the scenario:

Up to 35 mph, I get a rotational whomp whomp whomp noise from the back of the vehicle up to 35mph. From there its starts to get drowned out by road noise.

What I've done so far - replaced the rear bearings, greased the axle, checked the ujoints, checked the pads/rotors/calipers. No change in noise.

At a fairly high level of frustration/exasperation at this point. Everything else on the vehicle runs like the day I bought it, and when I get this figured out I'm 'back to normal.' Thanks in advance for any insight here!

 

[Hungryhawk]

Did you move tires around? Try replacing one rear side with spare-drive listen. Then move spare to other side -repeat. Then do same for front 2 wheels.
just labor -no cost to do.
Look carefully at exhaust pipe hangers.
my 2 cents

 

[ArthurKotb]

If the noise speeds up with the vehicle then I too would guess a tire. A belt can separate from the tire and cause that problem.

 

[Lemming]

It may also be the rear diff. Not rare for them to fail.

 

[ArthurKotb]

It may also be the rear diff. Not rare for them to fail.

I had a rear diff go out on me once; no warning. This was on a Plymouth. As I was accelerating there was a very large bang and the feeling that I had been rear-ended. Just coasting brought no sound at all, only when I accelerated, hard or soft.

If the sound the OP is hearing grows faster with speed, my hunch would be on a tire. I've heard a lot of them make that sound as they go down the road. It will just get worse and eventually separate. It will either unroll or explode. I had one explode. :-(

 

[mchestnut]

Ok - just wanted to update on where this landed. After switching out both rear bearings and finding out those were not the issue in my case, I ordered a replacement rear diff/3rd member from East Coast Gear Supply. Price was the same as local part yards, new Koyo components, and came with a warranty. Got it installed yesterday and noise is gone! Diff ran me approx $750, install was $400. Finally driving my otherwise great 2007 4Runner around in peace and quiet = priceless. Hope this helps get somebody with similar issues to the finish line faster!

 

[ArthurKotb]

I've never heard of a Toyota differential going out on anyone but I'm glad you found and resolved the problem. Thanks for posting the solution here for anyone in the future. Happy trails

 

[mchestnut]

Yes - I got that fun sinking feeling in my gut when it wasn't showing as a common problem. That's why I chose the rear bearings first, and after swapping those got an additional layer of heartburn when the noise didn't change at all. All along however it was very obviously coming from the back half of the vehicle. I should also mention it was creating other noises, so while I was about 95% confident it was the rear differential I was also mentally preparing myself for additional issues following the rear diff swap. Fortunately it was only the rear diff (one of the two if not both pinion bearings within the diff) that was bad, and all noises stopped following the swap. After digging for a while I did find a string addressing the issue, apparently I'm not the only lucky one out there...

Issue:

Rear Differential Noise / Rebuild?

Part - ECGS - $755 + $450 core charge:

Toyota V6 8''- Pickup, 4runner,FJ Criuser

Install Steps:

New 3rd member install

 

[CookieRoe]

I have a failing rear pinion bearing which has been making whirling sounds for some time now. Toyota wants $1800 for the fix (new pinion bearing + cost of removing it, etc). I have yet to find a shop that will tackle this cheaply around where I live, very frustrating. Great to hear you found a fix!