Everything is alright with my truck, but I just wanted to get some input from other people on this issue...

At higher speeds (70MPH and higher), I have a noticeable gear whine from my truck, though at that speed the pitch is very high. I find it most noticeable at around 80MPH if I'm in the left lane, as the sound will bounce off the jersey wall and back at the truck making it more audible.

I understand these trucks have a gear whine as the transfer case is gear driven rather than chain driven, I'm just trying to get an idea of what everyone elses experience has been.

 

That is odd, I only get whine when going too quick in low, never in high. Have you done any recent work on your t-case/diffs?

 

I've not, though it's yearly flush and fill is coming up. But it's make the noise since day 1 when I drove it home, day two, after the first fluid change, and every day since.

It's never gotten any louder.

 

I have some gear whine and high-frequency vibrations above 65. I flushed and filled my transfer case (and diffs) recently, and it seemed to make the whine slightly less noticeable. I even parked the truck on an incline with the right wheel lower so that I could get more oil in the transfer case than on level ground.

 

I run the 85W140 oil, and I added this and it seemed to quiet a bit more.

LUBEGARD Gear Fluid Supplement

Available in lots of places.

 

Hamal,
How many miles on the truck, when was the last time the drive train, tranny, diffs and t/case were serviced and what gear oil are you using?

 

I had the exact same problem (my whine was actually pretty loud past 70) so I followed these instructions and have noticed improvement, although the whine does not completely go away. From the research I did, the whine isn't a symptom of any malfunctions (but draining your T/case is a good way to see if there are any problems) and is just how these T/cases sound sometimes. It's a fairly common thing. Follow this advice if you want to hear some improvement, though!

 

The whine will never completely go away because we run a geared t/case and that is a normal sound.

 

It had 98k when I bought it, I'm at 107k or so now.

When I did the fluids on day two, the transfer case oil came out clean but well worn, as did the front and rear diff oil.

I used Valvoline Synthetic 75W-90 in the diffs and t-case.

 

Think seriously about using 85 or 75/140 in the t/case to help with the whine.