Any ides out there? 06 Megacab, 6'' Superlift, 35'' Nitto Grappler alltrains, aftermarket exhaust(not sure of brand) but the sound drives me nuts...can hear it on passenger side more, I thought maybe it was air on the grill??

 

Check all your ujoints after a drive, for heat and the usual obvious signs of failure. Most of the sealed units come too dry to start with. That would be my first check. Is it speed related (pitch change as rotation speed changes)?

 

Driveshaft carrier bearing?

 

I suspected the driveshaft carrier bearing. After driving it 20 miles on the freeway I got up under the truck felt the bearing carrier and it isn't discolored or super hot that you can't hold your hand on it. I also checked for any visual signs of bearing failures on the wheels. All four wheels you can hold your hand on the hub or axle housing. The transfercase gets pretty hot but it doesn't seem it is overly hot like one would think if a bearing was going out. I'm wondering if it is the aftermarket exhaust system. Maybe a exhaust drone. But I can get the truck up to 50+mph drop it into neutral, let the rpm drop to idle(750) and while it is rolling down the road I can still hear it.. ?????

 

I had a carrier bearing do that after I went thru a deep puddle of water, the next morning after it sat all night is when it started squealing . It didn't get hot, but when I loosened the carrier assembly, and spun it, I could feel the roughness in it. I brought it to a tranny shop to press the whole mess back together, I didn't want to mess up my new bearing hammering it together, gave the guy a $20.

 

I will remove the bearing cradle bracket from the truck and see if it is dry sounding when I spin it. I will report my findings....

 

Remove your front drive shaft and see if the vibration stops. Mine did the same thing at about 72 mph and above and it was the front driveshaft. That is, assuming it's 4X4.

 

Randal, yes it is 4x4. Did you have to replace the drive shaft with a new one or install new u-joints?...so, if it is the drive shaft then what??

 

Well, I had the U-joints replaced and put it back under my truck and the vibration was still there. So, I took it to a different shop to have it balanced and they said the first shop put the wrong U-joints in. The second shop quoted me a price of around $250 (i think) to install new U-joints and balance. Well, I did a little research and found that I could buy a brand new one (complete assembly, U-joints and all) for about $2 more than what they quoted me to fix the old one so I bought the new one. Put it under the truck and the vibration is 90% gone. It's still there but I have to really pay attention to feel it now.

 

Well I took the truck over to a good friends exhaust shop and come to find out that the exhaust system is stock and the muffler has been removed and a nice chrome tip has been added. He thinks it very well could be the exhaust drone or the exhaust resinating right off the turbo......????

 

Well, a muffler was installed and it still makes the noise. I removed the front driveshaft and it went away. The u-joints move smooth, no binding, no discoloration, all looks normal. The output driveline flange on the transfercase spins free but it does sound like the bearing is noisy. I used my mechanics stethoscope to listen while I was spinning the flange. I'm just not sure. So I went to the freeway for a test drive, engaged the transfercase into 4wd and no noise present. So is the noise not there due to no load on output shaft or is it the driveline????? anyone have any input???? I'm taking the truck back to dealer on Sat so they can fix it. It does have a implied warranty so the owner said to bring it to him. It is a 3 hour drive or I would of done that sooner...Oh, and what a pain it is to get the torx bolts out!!! Is there a special long shank torx for that????

 

Do you know about the "special" (cardan?) grease point on your front shaft? Someone can chime in with a proper name as my truck is an 03 so I don't have it. It takes a grease needle applicator and is a pain to find from what I've heard here.

I don't know if it would be your problem but it possible no one has greased it. I believe there is a label under your hood about it.

Cya

 

Mine did this also, put on a t-case indexing ring and it took care of my problems. Pretty common w/6" lift on these trucks. Had all the same symptoms. Your front driveshaft u-joints are exceeding their factory designed limits. They are not necessarily binding, but put to enough of an angle as to make a harse roaring noise.

 

There is a label under the hood about the greasing the u-joints at every oil change. The u-joints feel smooth when working them back and fourth by hand. But the bearing in the transfercase on the front output shaft that has a dry sound to it when you spin by hand. I can understand how this sound would magnify when the driveshaft is hooked to it. Does anyone here have any experience on romoving the rear cover off the NP-273 transfercase or what it will take to replace the bearing on the front output shaft. I wieghing the option of how much it will cost me for the dealer to have my truck for a week. 1. $100+ round trip in gas/food(3 hr drive one way) 2. Possibly a rent a car for a week. 3. Another $100+ in gas/food to go pick it back up. Not ot mention the two days of my time taking and picking up the truck....-vs- just fixing it myself. Bearing is a common 6011...I just don't want to have to remove the transfercase from the truck. it would save me a lot of work..

 

Have u checked the t/c fluid?