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

Ok final consensus after having it replaced. Howling is still there in the same range, but it is quieter. Noise is hardly there when the differential is cold but after driving for a while it gets noticeably louder. I can still easily hear it, but it isn't nearly as loud....yet.

 

This is exactly how my replacement went a couple months ago. At first I was like "Yay it is fixed!" By then next morning is was like "......shit......no it isn't....."

 

She has always wanted a tacoma.

 

I get this howl right at 55-59 mph. It doesn't change with speed, road surface, etc. I got the LCAs plugged, and the lower speed howl went away. This really sounds like the same issue to me, not a differential. I've been taping up holes in the frame on-by-one to see if that solves anything. So far no luck.

 

If the howl is throttle sensitive, meaning you can make it start or stop by feathering the throttle, it's differential related and you can stop taping holes. That is the right speed range for the differential noise.

 

4x4 TRD Sport DCLB no howling

 

Throttle has nothing to do with mine. TRD Sport DCLB.

 

I'm all set to put on a lift and new tires but want to hold off until I get this documented at the dealer. Don't want them telling me its the lift that I put on that caused this howl....

 

I will let people form their own opinions. This video is with the new differential, less than 90 miles on it, second day after my original one was replaced.




For reference here is the original video I posted with my original differential

Yes I realize they are two separate Youtube accounts, I have no idea how I created the first one because I can't find what email address I used and it isn't linked to my normal email.

 

Believe you said it was quiet when you had a load in the bed. Wouldn't think it's a worn diff if that's the case. Plus, a lot of these trucks howl right from the start.

 

Could have made the same video in my truck!!!

 

I'll be waiting to hear the results.

 

Might want to stop by the local liquor store to get something to add to that dealership coffee!!!lol

 

Lol

 

If this is true for all of us, then its obviously an airflow related howl from the rear drive shaft or connected exterior part. The pitch of the front end can disturb the vortex whistle that is created when the holes in the swiss cheese line up.

 

Anything's possible. I don't think this is the case because you can start/stop the howl, just by feathering the throttle.

 

Wtf does feathering the throttle mean. I mean I know but when does it howl. When you give it gas or when you let off the gas. Would be a nice clarification for those of us without a "howl"

 

Howls when going 50-60 mph and and just touch your foot to the throttle. Like if your going the speed limit, say 55mph and you want to maintain that speed on flat ground.

 

Gotcha thanks.

 

The noise is similar but I have to disagree for a few reasons.

First, even though my howl did not go away when they replaced the differential, the sound did change. It's worse now and doesn't just happen under light throttle like before. Now it happens under light throttle and deceleration and is louder. I'd be inclined to think that if the differential wasn't involved that replacing it would have had no impact on the noise. Even a negative impact implies that they were on the right track.

Second, Smitty's dealer ran his on a lift and used a stethoscope to pinpoint the howl to the differential. Since it was on a lift, there was no airflow across any holes and the howl was there and easily pinpointed to the differential.

Third, my own experience and that of others (including but no limited to the service manager and regional service manager who are lifelong mechanics) is that throttle-sensitive noises coming from the rear of a vehicle are symptoms of a poorly setup or worn 3rd member.

I'll also add that while I still think that

$29 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 is too thin for truck differentials, thicker fluid only muffles the sound and doesn't cure it. Don't ask how I know that because I obviously wouldn't be dumb enough to put a different viscosity fluid in a differential that was still under warranty.