3rd Gen Poll: Rear End Noise howling when feathering throttle

Well just drove mine home after having it replaced.

First got on the freeway (right by the dealership, less than 5 minutes away) and got to 59 getting on the freeway, feathered the throttle. Silence. I was so happy.

Continued my drive home....started to hear some howling around that speed but it was very faint and I could completely live with it. In fact I wasn't even 100% sure it was related to the same cause as before because I couldn't fully discern if it came on and off with the throttle. There was just a very very slight howling noise in the background at the level of "would not notice unless I was looking for it."

Towards the end of my commute home (I have a 30 minute highway commute total), got it to 59 on a downhill and it howled ALMOST AS LOUD as before it was replaced.

Well shit. Im not going back to the dealership again for it.

I hope to everything there is to hope to that it was a fluke on the last section and it was the wind angled perfectly over some part of the truck but deep down I know it wasn't as I took my foot off the gas and it decreased dramatically. My initial impression is that is was quiet until the diff fluid had time to heat up. They told me at the dealership it was perfect and if I had just driven it that short distance on the freeway (same loop I took with the service adviser) I would have completely agreed.

I'll update a bit down the line with anything new. I won't be going for a 3rd differential unless Toyota releases something official promising silence.

If it returns just as loud and there is no fix, along with the other issues I have I'm sorry, but I'm not keeping the truck. I'll find something else to satisfy my manual transmission and offroad fix.

 

Checked the fluid level?
Follow a proper break in procedure?

 

Mine gets louder once the diff fluid heats up.

 

It is brand new, I didn't check the fluid level before leaving the dealership. All the service manager told me was that to replace and fill the new diff (just carrier assembly or third member) it took them about 2 hours. So it was filled by the same guys in the shop, I would hope if they know how to replace an entire third member they know how to add the proper amount of fluid. But I agree anything is possible.

As for the break in procedure I did what I could in traffic on the way home, I don't really get to choose what speed to go. My speed varied, all the way from stop and go traffic to 70 mph, and I didn't drive it for more than 30 minutes. I will assume the shop foreman didn't drop the clutch and do donuts after putting the new diff in so I would say so far so good on the break in.

I don't know what else to do, I can't see a differential being so sensitive that it starts howling within 30 minutes of normal driving. If that were the case every single one would howl.

 

Not so much the diff being sensitive, but the fluid breaking down from heat before it's taken a set.

 

We gonna have to live with it bassman?

 

Better drink all the coffee you can!! Get your money's worth! How many new Tacomas you test drove and heard the howl?

 

So you had 5 differential puts in ???

 

You notice yours being any quieter when it's cold? Like just starting out in the morning?

 

Mine's the same way. Howl doesn't start till truck's been running about 10 mins.

 

Is it when you let off the throttle or give it gas?

 

Guess I'll live with it for now, and hope for a fix!

 

"Total at the dealer has been five new ones"
Ones ? That was quite vague really.

 

The post right before his asked how many new Tacomas he drove that howled...

 

Should not have to reference previous postings. Especially on previous pages.

 

Well then have fun not understanding half of the content on this site.

 

True most of it is bad grammar and bs anyway

 

Oil viscosity plays a major role in the the noise of a diff. Once heated up it, sounds like the oil is too thin.

A friend of mine had this issue on a g35 sedan and we swapped fluids and suddenly it started making more noise. Swapped to a heavier weight oil and it went away.

 

My SR5 is quiet. But it is RWD.

I am surprised you didn't convince her to get a different vehicle?

 

well I can be added to the list. I thought that it was noise coming from the front LCA's but its clearly coming from the back of the truck. I need to get it in for an oil change (10k) and I'll have them look at it.

Mine does it from 50-60 mph when I'm light on the gas. Below this speed, its quiet....