On my daughter’s 2006 Sport V6 RWD, with approx 150,000 miles, there is a whine in the rear differential. It’s been going on for over a year/10,000 miles. I’ve kept fluid changed at 50,000 (Mobil 1 synthetic 75W90LS-limited slip).

Truck is in great shape otherwise, and I’ve done all the maintenance to keep it that way. We hope to get another 100,000 miles out of it.

We’re keeping an ear on it, but I think it’s inevitable the diff will need maintenance. And we don’t want to drop a lot of cash in it.

The last time she stopped by after a long interstate drive, approx 60 degrees ambient temp, I crawled under it and felt the axle ends at the wheel and they were cool to the touch. The pumpkin was fairly hot (I could only keep my hand on it for about 5sec). I’m unsure if that’s a problem or not.

I’m thinking we keep running it until the noise gets considerably worse, then buy a new third member from ECGS Toyota V6 8''- Pickup, 4runner,FJ Criuser. I’m a decent mechanic and assume I can handle the swap, but I’ve never done this. Does this sound like a good plan? Anything I should be thinking about differently? Can I do it?

are you certain its not a bearing? I was convinced I had a bad rear diff and it turned out to be a bearing. THese bearings can be bad with still zero play in the wheel.

Do you mean axle bearing at the wheel? No I’m not sure. All I’ve done is feel for temp. How can I diagnose?

Whine is caused by worn ring and pinions. You can try to run some additive or do an oil change, but its most likely on its way out with that mileage.

The ECGS system makes it very easy to install, its just draining fluid, loosen bolts, install, tighten bolts, fill oil.

In the meantime, I'd drain the Mobil-1 and refill with Lucas 85W-140 per ECGS recommendation linked below. It won't fix worn bearings, but it may quiet things down and prolong the service life of you current diff & gears.

Red Line Shock Proof Heavy is also nice for high-mileage diffs.

ECGS Gear Oil Recommendation

Thanks, I hadn’t seen that. Are thes 2WDs limited slip requiring the additive?

One way is once you are at a speed that you hear it clearly, pull a hard left, Does the noise go away briefly? Doing this will shift most of the weight off the left bearings briefly, which will reduce the noise greatly. then do right side.

I would guess its the pinion bearing. Mine has been doing the same thing this past couple months. A faint waaaa noise when coasting at 45mph. This seems to be the culprit from what I've read, and yes changing the 3rd member out w/ ECGS should fix that.

The funny part about mine is that it's already a 3rd member from ECGS.

I have the same whine noise. 2006 4wd with 150,000 miles. Does yours go away in neutral?


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They have 5 yrs warranty, no?

Yes and I also have a spare gearset sitting in my basement so I'm not too worried. I'm not sure they would warranty it as it hasn't really 'failed' but I really have no clue on that part.

I talked to the tech at ECGS today, he said they are open differentials on the 2WD, not limited slip...

I was convinced it was a wheel bearing. It was not.

We are putting and ECG unit in tomorrow morning. I was going to send it to Zuk, but I can't have the down time.

Hey iBison, what is your vehicle? I tried looking in your info link but no worky. Mine is a RWD all stock and I only want to keep it all stock. Would appreciate any tips/instructions/pictures - I’ve never done this type of work before...

The worst part is putting the parking brake back together if you pull the axles all the way out. We did in order to clean the axles and the tubes to minimize any bearing particles that are in there. When we drained the fluid the oil looked like metallic paint. Check this link, page 5 has the install. We had done the wheel bearings before so I only looked that up when I was looking up torque specs etc. we used RTV instead of a gasket.

Step by step removal and installation of e-locker 3rd member | Tacoma World