D/A Overdrive is noticably noisier in cab...

[Rock]

Was in the high country this weekend and noticed after driving 150+ miles over 2 mountain passes, the 3rd pass going down the mountain I noticed a low frequency type noise...I guess you could call it vibration. It was noticable in the cab. I had 4 hi engaged. I had tow/haul engaged to help reduce the amount of braking to keep a safe speed.

After getting down the pass to clear roads, back in 2 hi and tow/haul disengaged, I noticed the noise again around 60-65 mph. It only occured while accelerating. It also only occured at these speeds.

Back in town today and noticed it again while going up hills accelarating. I turned the overdrive off and the noise went away.

Where can I possibly begin trouble shooting? I checked trans. fluid levels 2x and it's in the hash marks...

Thanks in advance.

[Kennedy]

What are you running for exhaust?

[Jim Brzozowski]

Yeah, if you don't think that exaust resonates, just walk up to the back of your truck and pop your hand against the tail pipe and listen to it ring. Between the exhaust ring, the turbo whine and a few other natural occuring sounds. It's easy to jump to the wrong conclusion. I know I've done it a time or two. If it gets worse, of course better get it checked out.

[Rock]

Kennedy:

My exhaust is stock. The thing is, I've never noticed it to be this loud before...

Another note: I had someone else ask me if I could "turn my front driveshaft when in park" after reading this post...I sure can, just don't know where they were going with that thought.

[DmaxMaverick]

Originally posted by Rock:
Kennedy:

My exhaust is stock. The thing is, I've never noticed it to be this loud before...

Another note: I had someone else ask me if I could "turn my front driveshaft when in park" after reading this post...I sure can, just don't know where they were going with that thought. The reason for checking the front shaft is to make sure the front diff and/or transfer case is not "locked in" when it shouldn't be. If it were to be locked, additional noise would be expected, but there would be something wrong with the front diff or transfer case. If both the front diff and transfer case were locked in, you would also notice tire scrubbing (binding) when turning, like it will do when 4 X 4 is selected. If your front shaft turns free, then that is not the problem. Keep looking. Good luck!