When in 4WD, at speeds over about 45 MPH, it makes an audible vibration-like sound, which goes away immediately if I go back into 2WD. I swear this wasn't the case when I first test drove it, but maybe I just didn't get it up fast enough in 4WD mode.

I called the dealer and talked with the head of the service department, and he said this is normal for the part time 4WD models, but that it would not hurt the vehicle (I should hope not!).

So can anyone confirm for me that this noise is normal at highway speeds?

 

Well this might not be much help as my truck is a 2nd gen, however mine does it as well. It's more of a low-pitched vibration sound than actual seat or truck vibration, but nonetheless it is evident.

 

my '03 tacoma does not make any extra noises in 4wd. I have had it up to and beyond the speed that you're talking about. I hope everything is OK!

 

thanks ewarner. Anyone out there with a 4th gen V6 that can testify?

 

No vibration, no noise in 4WD.
Have you regularly (every month as per manual) switched from 2WD to 4WD to lubricate the parts?

 

I don't hear any noise when in 4WD at speeds in excess of 45 MPH, or any other speeds for that matter.

The only slight difference I notice between 2WD and 4WD is in the feel in the steering wheel during cornering. It feels as if it is "binding" slightly.

 

Yes, I have regularly used the 4WD. My real fear is that last time I went off-roading, I crunched something, and now something is off-balance, causing the vibration when I get going fast.

Any other ideas?

I think I'll just end up taking it to the dealership, but I wanted to know for sure that this doesn't happen to other people.

 

Damaged driveshaft?

 

but if it was the driveshaft he'd know right away

maybe it's the axles?