Loud grinding noise from transmission area

[phokur]

Hi all, I have been under the truck twice and even had a tech look at it with no idea where the noise is coming from. It started when I was full throttle in left-hand turns, I got a rotational grinding noise from somewhere under my feet. It has progressively gotten worse as now whenever I release the clutch or give full throttle it grinds. Neutral/clutch engagement stops the noise completely. I have checked to make sure everything is tight, greased, and nothing is rubbing (no clean metal under the truck). Anybody else encounter this?

 

Update: After reading more around, I'll clarify some more. I get this noise, while under gas, in all gears at any speed. I get it primarily at starts or when I just mash the gas. Hitting a bump also gives me the noise. Hope that helps!

[phokur]

Started snowing here so went to throw into 4wd today, no go. High and low both only engage the rear. This mean new transfer case?

[Oizarod115]

if you've got grinding in the t-case you're going to have metal in the fluid, pull the fill plug and see if it has any fluid in it, then pull the drain plug and see if large chunks of metal come out with it...

 

you also may be able to shine a light up in the holes and see if something is destructed.

[phokur]

Thanks for the tip! I will get it up on the lift when I get access.

A related question, when my front wheels spin, should my front driveshaft be spinning or does the front differential disengage them?

[phokur]

Fixed, was actually two issues.

I had no 4x4 because the vacuum lines slipped off of the front diff.

The noise was caused by a broken exhaust clamp making the exhaust vibrate against my transfer case crossover.