Howling noise when letting off gas after new rear diff install

Hey all,

I got a new rear diff from ECGS (East Coast Gear Supply) with 4.88 gearing and an ARB air locker on it. I swapped out the shells today and it went smoothly. When driving back though, I noticed when I let off the gas - I heard a bit of a howl, not ultra loud, but definitely notable and always when letting off the juice.

How concerned should I be? Is this something I did wrong or should I talk to ECGS? Okay to ignore?

My first search for this lead me to "If you notice that the howling noise only occurs during deceleration, then it is a good indicator that the pinion-bearing preload has loosened" - which if I understand correctly, sounds like something from the gear shop not being done right? I wanna see what folk here think about it before I give ECGS a call.


Thanks for any help all.

 

Mine howled really loud at first. After the first oil change it seemed to slowly go away some. I still hear it occasionally but I upgraded to more aggressive tires so I have to listen for it now. I also heard a slight howl on the highway but that is all but completely gone. I've got around 10,000 miles now. If you are really worried, you could call. Their customer service was top notch for me

 

For what its worth, when i installed a gm 12 bolt rear in my 66 gto with 4.56 gears it did the same as the op's claim. That 421 super duty motor still blew it up, just took longer.

 

From having diffs changed in two different 4x4s, you shouldn't have any noise. One 4x4 I use to have, I had a local Napa replace a rear diff, and I first had noise on deceleration at low speeds, then again at high speeds! Took them three attempts, and then it was quiet!

A friend at an off-road shop told me that they just didn't do it right. This friend then did another 4x4 for me (front and rear TrueTracs in a Jeep TJ) and they've been quiet.

 

Thanks for the replies, seems like the experience is not uncommon I guess

 

Just an update on this - I contacted ECGS about the noise, they were willing for me to send in the assembly so they could look at it and send back. I said nah that won't work, I need my truck - so they agreed to send me an entirely new assembly for me to swap in and then I'll send the howling one (though they took a deposit on my CC for this option).

Anyway, it's supposed to arrive today, I'm planning on installing tomorrow. Fingers crossed for no issues with this one, will let y'all know.

 

Yes, please update us. On their site, they acknowledge that an increased howling noise is to be expected and linked a Toyota TSB.

I had already placed an order anticipating this.

 

Oh do they? Can you link to the page, I'm blind and cannot see it

 

https://eastcoastgearsupply.com/i-23993416-8-75-tacoma-elocker-third.html



Of course, I assume a drastic howling noise would definitely be a problem.

 

I'm curious about any change. I've been running mine for around 10000+ miles without issue but I had a noticable howl from the start. Louder on deceleration

 

Oh nice - yeah I am replacing an Auto / Non-E-locker - so it looks like a different third housing: https://eastcoastgearsupply.com/i-23993418-2016-tacoma-auto-non-elocker-third.html which interestingly, there is no TSB linked on that 8" diff.

I guess that's a different type of vibration. I really hope it's the pinion bearing. Dumb question that I should've asked them, do all third assemblies with new gearing ratios require new pinion bearings, or can they reuse the bearings from other housings that people ship back? Trying to understand how that can slip through the process.

 

New diff on today. Took it for a little drive and it was absolutely silent. Only got to about 40-45mph. I was going to do a second run on a highway after cooling down but my brakes are fucked. Maybe I screwed up my bleeding since I disconnected the rears to get the axles out. I'll try a fresh bleed tomorrow, as the brakes are ultra squishy to the point of being almost not there.

I've been reading about other people running into the same issues with doing traditional bleeding. I'm probably just gonna take it to a dealer for a bleed if I can't get it responding properly tomorrow. Sigh.

At least the new diff is SILENT. Yay

 

I had 3 ECGS 4.88 Elocker Diffs break in the last year. I gave up and put my stock Sport 8.4 back in. After #3 they said they were out of 8” 4.88’s and tried to land me in a discounted drop in D60. When they break they don’t sound like a howl. They start with a little tick when you decelerate, from there it gets more violent and feels like a bad ujoint. Two let go in the freeway and one driving about 30-35 on a back road.

 

Well if that isn't just the most reassuring thing to read ever.

 

They absolutely bend over backwards to help you, I’ll give them that. Eating the 3 $700 tow bills,18 quarts of Lucas gear oil and swapping entire housings twice and 3rd members 3 times has left me a little bitter.

 

Yeah I'm already annoyed that I have to do the labor of a diff swap twice. I actually paid to get the front installed because I couldn't be bothered with the hassle. I keep thinking about how infuriated I would be if I had have paid for the back only to have to pay again.

Sorry to hear about your experiences. Any idea about the root cause?

 

They said possibly a bend housing, but I don’t think so, I bought the axle from a pretty well known reputable local TW member that swapped in an 8.4.

 

Okay I got wife to help with brake bleed and got rid of all the bubbles. Brakes are Gucci.

Took the truck up to about 65mph and let off the gas. Not a peep. Now all I hear are my loud tyres. Life is good. Will send old egg back to ECGS tomo.