Howling sound?

My 2014 Tacoma began making a "howling" sound, maybe a whine, under hard acceleration from a stop. It doesn't howl/whine at a stand still when accelerating the engine. It won't howl under acceleration after under way. I have noticed it will howl/whine briefly when flexing over a bump hard enough to move the suspension at nearly any speed. This makes me think driveshaft and thought I figured it out in the carrier bearing. I removed the carrier bearing, not completely off the driveshaft, from the frame and it spun easily on the drive shaft making be believe it may not be the carrier bearing.

Initially it sounded and felt like it was coming from right in front of the firewall. After trying different methods to recreate the howl, I found that the sound and the vibration move from the firewall area all the way to the back seat.

Based on my description, a mechanic friend put money on the catalytic converter. Would have never occurred to me that this is the cause and based on my above experience, it's not. But thought I'd mention it.

2014 TRD Sport with a TRD supercharger, initially thought a SC bearing, but won't make noise under just accelerating the engine or under boost when under way.

1006xxx miles. Automatic tranny. 4WD.

Any help would be appreciated. Mountain States can't get me in until Feb 18th.

 

Did you ever figure out the issue?

 

It was the gas tank heat shield rubbing on the driveshaft. It had gotten bent in the previous snowstorm. Coincidently, a co-workers third gen did the exact same thing. I overheard him telling someone about it and got a laugh about it. He and I both ended up at the dealership trying to figure out what was going on. While I didn't enjoy paying the dealer, it was a relief to find it was such a minor problem and fix.

 

That's a lotta miles. Or maybe one x too many?

 

Yes, one too many zeros. 106,xxx. Just hit 115,000 this week.

 

Nothing wrong with a million mile Tacoma, @Clearwater Bill !

 

Truth. Just making a wise crack.

OP, glad your problem was found to be simple.