Transfer case gone bad

So i've had my 2011 tacoma since November 2013. I used to get a whistle/hum when driving at 75mph, I thought it was the crappy OEM tires. Got some KO2's installed and still had it. Lately, I've had a hum on deceleration between 65-55mph, then another from 35-30mph. Truck drove fine so I really didn't do much about it. My warranty is up in July, so i dropped the truck off at the dealer on monday to get it checked out - turns out they found metal shavings / chunks in the t-case!! And that the bearings were bad!! Wow. They replaced the t-case with a brand new unit and it's all good to go. Anyone else had this issue? I cant believe the t-case only last 50,000 miles (i'm sure i could have driven it more, as who knows how long it's been bad for? Been making noises since 25,000 miles).

Want to say thanks to Erin Park Toyota for taking care of the problem with no issues.

 

I have never heard of that happening before. Since they replaced it with new, I'd say you don't have anything to worry about.
Was there fluid in it? If there was, I'd guess at oil pump failure.

 

There was fluid in it - test says they found metal chunks in it. Then when disassembled, they found damage to gears and worn bearings.

Well, after driving it for 2 days - the noise that i had before is still there. I always thought it was the rear diff / pinion bearing but they told me it was the t-case. Bringing it back in on Wednesday to have it checked out again.

 

When I started reading through your post the first time, my initial thought was about the rubber strip across the top of the windshield. I disregarded that possibility when you mentioned the transfer case issue, but since that has been corrected and the problem persists, its time to revisit it.

Some have experienced it as a whistle, others more as a kazoo sound. If you look at the rubber strip along the top of the windshield, there is a kind of a flap wedging against the sheet metal opposite the glass. You can use something like a guitar pick to pull it away from the sheet metal, and see that there is actually a fairly significant void in there.

So what happens, is the air running over your truck is moving fast, hence low pressure up at the top, while slightly higher pressure along the sides where air is ramming straight into it. So literally what is happening, is it is sucking air out from that space between the rubber and the sheet metal.

Here is an experiment that you can do to confirm it; get yourself some 2" masking tape, and run a strip of it over the rubber strip along the top of the windshield. Stick it down nice and firmly to the windshield and the sheet metal. Then go for a drive and see if the problem is solved -- at least before the masking tape gets ripped off.

If that solves the problem, get yourself some soft clear silicon from home depot, like bathroom silicon I, and fill that void. You want to use a softer silicon because if that ever has to come off to replace the windshield, windshield silicon can be pretty tough.

 

Interesting. That actually sounds like a fix to the other issue i was having when I'm driving down a highway at 70mph + with a heavy crosswind. I get a kazoo type of sound. I will definitely check in to that.

As for the 65-55 deceleration, I'm 99% sure it is something mechanical as it happens like clockwork, same time, every time, and only happens when in gear.