4A turbo spooling sound?

[fishrising]

So, the last two days here were my first with my 19 Expy in the snow. And the first time I really played with 4A (don't have 4L, and this is my 2nd ecoboost v6 motor). After putting it in 4A I noticed what sounded like a turbo spooling up while accelerating, at any rate. I tried various levels of throttle pressure. Even with minimal throttle pressure, watching the traction gauge, and not seeing any drive being given to the front wheels, I hear it. When switching back to 2A, and doing the same exact tests the noise was not there. I tried the same thing today, on clear/dry roads, with the same results.

Could these be the turbos I am hearing? But only in 4A? Why would I hear them in 4A but not 2A?

Or could this be the mechanics of 4A, with a front differential being engaged and actually spinning? And I am therefore hearing that spooling/spinning/whirling noise? But if so, is it completely OK to leave in 4A full-time, say for a snowy 3 hour highway drive?

Anyone else notice the sound?

I wouldn't say the noise is loud, but I notice it. If I were to leave it with the dealer, and told them about it, they would probably test it and say "what noise?" Then I'd have to ride with them and point out the noise, at which point they would probably pick up on it.

 

[Squark]

I hear it in 4A as well. I think it's just the transfer case and front diff making sounds you don't normally hear in 2A. It is fine to leave it in 4A. If you're curious which wheels are getting power you can pull up the power distribution screen on your instrument panel. Under light acceleration it's mainly RWD, but give it some gas and it sends more power to the front wheels. You can also pull up a turbo boost gauge on the instrument panel to see that the sound isn't tied to the boost. To me, the boost is a whistling sound while the 4A sound is more of a faint whine.

 

[aggiegrad05]

I also hear....something when I am in 4A. It is a mechanical noise, not a whoosh, and sounds like it's coming from the front passenger side. I have always assumed it's just the t-case and front diff.

 

[edizzle]

turbos are more audible under load so theoretically they could be more a little more audible in 4wd

 

[shane_th_ee]

You could look at the boost gauge...

 

[Deadman]

Thats exactly why I let mine in 2 wheel drive. Less stuff spinning to wear out.

 

[Julio Walker]

I hear same thing. I’m taking to dealer tomorrow to have it check it out to make sure is within specs. I also have steering wheel play, along with three of four tires with uneven wear...with one edge sharper than other. So I’m thinking hubs, but we will see. Hopefully everything will be covered under warranty. 26 days in the shop out 3.5 months of owning it. Luckily I haven’t paid anything out of pocket....

 

[edizzle]

you have uneven tire wear in 3 months of ownership?

 

[fishrising]

I hear same thing. I’m taking to dealer tomorrow to have it check it out to make sure is within specs. I also have steering wheel play, along with three of four tires with uneven wear...with one edge sharper than other. So I’m thinking hubs, but we will see. Hopefully everything will be covered under warranty. 26 days in the shop out 3.5 months of owning it. Luckily I haven’t paid anything out of pocket....

Would love to hear what they have to say [re: 4A noise] once you get the truck back. I am assuming its normal, but never noticed it on AWD or "Auto 4wd" vehicles before (XC90, GL450), and even including my old previous 2006 Expy FX4 when in A4WD. My built Wrangler, I heard similar when in 4H and definitely when in 4L. Thanks!

 

[Soliyou]

I have the same 4A noise - but in addition mine has an audible gear whine around 2,000 rpm when 4A is engaged and the front wheels are powered.