Gear Whine after regearing

0.076 is the factory shim they just reused. I can bet that its too shallow.

 

Dude, are you serious? lmao How can you tell it's from that particular vehicle and size? I'm going to totally call them out on it.

So they probably didn't use one that came with the kit? I don't know much about patterns, but that one looks to me to not be perfectly centered.

 

It doesn't have to be perfectly centered. Slightly towards the toe or bottom. But that pattern looks shallow especially on the drive side.

 

That makes sense. My off road has an e locker, and my brother is saying those pics doesnt look like it has one. What do you guys see on that diff that would definitely tell me it's not from a 3rd gen off road? Thanks for the help!

 

Patterns are hard to read in pictures but that looks ok, maybe slightly shallow but acceptable. Doesn't really matter because definitely agree that doesn't look like an 8.75 elocker carrier so not your diff. Bet that's an "example" of your pattern. Backlash at 0.009" is a touch on the high side.

Won't get into it yet again but in-cab whine is common in these trucks and not indicative of improper gear mesh or setup.

This is how the 8.75" elocker carrier looks. https://www.tacomaworld.com/threads/trd-off-road-locker.486049/#post-14901599

 

I work on alot of diffs to know what it is. Centering the pattern isn't critical, but can be slightly adjusted with backlash. The pattern on that diff in the pic is a bit shallow. I know for fact that an 076 shim in your diff is def shallow and can be causing your significant whine.

 

The 8” rear diff is found on 3rd gen Sports, SR5, and SR. I have an Eaton 8” TV6 locker sitting in my office for a 2021 SR, it’s interchangeable with newer Tacomas so long as the spline number is the same.

 

You can tell by the carrier that the one pictured is not from a 3rd gen Tacoma, its from a 2009 model year or older.

 

That's just awesome. They sent me the pic and my brother actually called them the other day to ask what was up with the picture, and the shop owner basically told him he doesn't know what he's taking about, and that the picture was for sure of my differential.

I googled lots of pics too of the rear diff and none of them have the black casting on the carrier for the 8.75 off road, they all looked polished smooth to me. Not sure why the dude lied, other than saying if he had a pic for me after I asked him when the truck was done, but he really didn't. Not sure why he wouldn't just tell me he didn't.

I think I will just pull the trigger and have them put a nitro rear in and hope it gets better. I don't want to drive 2000 miles across country only to have to listen to the diff the entire time. They claim my truck is only one of 5 in the last 2 years to have sound issues like this. That and it's just one more reason I would want to sell this truck at this point. I love it but kinda tired of having to do all this stuff to get it to drive well.

 

I personally think you just need a pinion depth adjustment to alleviate the majority of the gear whine.

 

I don"t want to burst your bubble, but my 2020 MT trd pro has NO gear noise at any speed. Gear noise is from not being set up correctly. Not trying to be a know it all, but been doing this along time,, good luck..

 

Just spoke with another installer at justdifferential and the guy was super informative and helpful. I told him my situation, and that I am running 265/70/17(31.6") and he said that the smaller size tires could be a big contributor to the noise for sure. I'll see what he says about my "differential" the other tech sent me lol. Thanks for the info gents.

 

Here's what an 8.75 elocker rear looks like.

https://www.instagram.com/p/CDoOTF-AhQs/?igshid=6s7xp91xkofr

And here is what an 8" TV6 elocker looks like.

https://www.instagram.com/p/CD6T18NgvrZ/?igshid=v7suuayqc4mz

And an 8.2" elocker

https://www.instagram.com/p/CFUgz0HnF8M/?igshid=1eqp3h692xx4p


You can certainly see the difference between the 8.75 and the other 2.

 

Wow, super big difference! You have some awesome patterns too man. Wish I could have had you do my install haha. Have any of your installs on the third gen had slight whine, or is it pretty rare?

The guy got back to me and said its too hard to tell from the pics, but with what you showed it's pretty damn obvious lol.

His final advice was to put some nitro gear oil into the diff and it might help with the sound, since their stuff is proven to work better than the competition. Sounds like marketing to me.

Thanks for the pics!

 

If there is a whine, its very faint. Usually I have to tell em it's there for them to notice it. I think if Lucas 85w140 isn't letting the whine go away, Nitro oil won't do it either.

 

My rear diff whine has been reduced dramatically by changing the oil weight. I have nitro 4.88s.

A few weeks ago I replaced the oil in both diffs and the t-case as recommended by @Pablo8 on his Amsoil thread (https://www.tacomaworld.com/threads/amsoil-products-atf-mtf-gear-oils.639632/)

I changed from 80W-140 in front/rear to 75w90 in the front and 75W110 in the rear. The truck coasts easier and decelerates much less quickly. More importantly, the gear whine is almost unnoticeable now. With the heavier weight oil I could hear a very loud drone from about 57-66 mph. Now I can still hear it between 60-63, but it's probably only 40% as loud. It sounds more like the hum of knobby tires instead of a bomb dropping on top of you.

I'm stoked on the improvement. Thanks, Pablo8!

 

Excellent info

 

Anyones truck act like the rear diff was locked for a bit after regear? Tire chirp on slow corners kind of thing.

 

Sounds like something is wrong to me

 

Seriously wrong IMHO.