I posted a thread earlier about this "sound" accompanied by a very slight vibration from 55 or 57 up to about 65mph. I had just had the output shaft seal go bad so i replaced it, changed the fluid in the T-case. I got out between 1-2 quarts of pretty used but not tar fluid. I was a bit concerned when I had the driveshaft out that there was alot of play in the output shaft of the transfer case, both in and out and up and down. I went ahead and installed the seal and greased up the slip yoke and reassembled. Took it out and no changes, still have that sound. I had also checked the U-joints and they were in great shape when I had the driveshaft out. So I went ahead and checked the front and rear axle fluids. The front was fairly low so I changed out the fluid in it and gave it another test run, still have that noise. I am baffled. The problem is only in that speed range and only when in the throttle, the second you let off the pedal it goes away. It is worst if you let off the throttle at about 60 and then eas back into it, thats when it seems to be the worst. I am at a loss. What else should I check and what could this possibly be. Any ideas would be greatly appreciated.

I have that same slight whiney sounding vibration at speeds from 55-60mph. Can feel it in the pedal and steering wheel. If I stay on it at 60mph the slight sound and vibration stays as well. I dont know what
it might be...

Though at this point I'm guessing a few things, I just had my carrier bearing and driveshaft balanced under warranty for the same complaint. Threads on here have led me to believe that the carrier bearing may come misaligned from the factory - MDN's similar issue was finally solved when they spaced his carrier bearing down a 1/4" with steel plate and shimmed the front diff(I'm assuming they tipped the rear down to match). Anyways, after replacing my carrier bearing and sending the entire driveshaft out to be balanced(supposedly was fine), I'm still having the same sound at the same speeds under load. Its subtle and they(the stealerships) want to say 'can't duplicate' or its normal, etc. This is what I was told by 2 dealerships at 12,000 miles - now at 34k its a big enough problem that my carrier bearing was shot and they needed to spend the $ to send my driveline to an independent shop. Anyways, search MDN's posts and you should find the thread or contact me and I'll pass along the info he's given me. As much as I've read about this problem on here it really seems that it should be in a TSB or recall - its way too much money to fork out for a $45k truck for a factory related wear issue. (Kind of like their pitman/idler front end setup but thats for another thread...)

Well in response, my truck does not have a carrier bearing so that is out of the equation. I had also checked my driveshaft and all the weights are still attatched to it. It just seems odd to be that all of the sudden one day it started doing this........And it really sucks stuff like this happening at 74k.

Still sounds like a U-joint to me, but I could be wrong.

I hope you find it what ever it is, and keep us posted!

I checked them the first time I had the driveshaft out and they seemed ok to me, but I am no mechanical genious. So yesterday I took the driveshaft out again and had one of the guys in our shop check them, and he said they were in great shape, no play, well lubed and good to go. I did notice one more thing, this problem seems to be worse on slow accelleration, when I accellerate hard up to 70 it doesnt seem to be as loud or as bad, dont know if that helps any or not. Thanks for everyones comments so far.

My universals seemed tight, but i had a wobble and they where slapping on start/stop.

did you check your transmission yolk.... ive gone through 5 u-joints and still had a vibration and then on warranty they replaced my transmission yolk i also notices that the carrier bearing was worn and still had a bit of a vibration but they wouldnt fix it and said it was fine...... the yolk fixed most of the problem though

Could this be a rear axle issue? Noise does transfer up the driveline.

May be worth popping the rear cover and check it out.

Exactly the same symptoms I had. Turned out to be a bad wheel bearing. It would make a roaring sound from 55-65 and quiet at other speeds. Jacked up the front and there was a half inch of play in the left front wheel.

Exactly the same symptoms I had. Turned out to be a bad wheel bearing. It would make a roaring sound from 55-65 and quiet at other speeds. Jacked up the front and there was a half inch of play in the left front wh eel.

:agreed: x 2

Tyweston1,

You said you noticed a lot of play in the transfer case tailshaft and the fluid was pretty used up....
I had the same exact problem. Unfortunately, the transfer case pump was bad and the bearings burned up in the case. I needed a total transfer case replacement.

Hope this isn't it.

Your symptoms sound the same as my wifes' truck. It almost sounded like she had 44'' swappers that where out of balanced. The sound got really loud in the cab after 1 week and the dealer replaced the wheel bearing. The truck sounds and steers like new!

The problem is only in that speed range and only when in the throttle, the second you let off the pedal it goes away. It is worst if you let off the throttle at about 60 and then eas back into it, thats when it seems to be the worst. I am at a loss.

I thought about the front wheel bearing at first too, but his statement made me think otherwise.

In the throttle it vibrates, and let off it is smooth, has always been a U-Joint in the past for me and everything from my old 1963 Impala Convertible to my last truck, this truck has held up well to them.

Might be something else, But finding the culprit u-joint can sometimes be a bear! I had to replace all of them before, one at a time till it went away.

Just my 2 cent worth.............................

Had the same up / down and in /out play in the output shaft. The movement is caused because the snap ring that holds the output shaft rear bearing in the case has come out of the groove in the case, and let the shaft move into the case, also the output shaft bushing in the case is worn.
Call Eric @ Merchant Automotive and get a pump upgrade and a rear housing.

Question on the output shaft play I have. When I was pushing up and down on the shaft I think I could see the rear ball bearing in the back of the T-Case moving up and down with the shaft. Is there supposed to be any up and down with that bearing or is it supposed to be held in the case and not moving, if it is not supposed to be moving then maybe thats my problem. Thanks for all the help guys.

If you can see the ball bearing, it is not good!

That bearing is about 3-4 inches inside the tailshaft, so that rear bushing must be a mess.

The rear bearing is in a machined pocket, and held there with a snapring.
http://www.dieselplace.com/forum/showthread.php?t=140732&page=5
Look at post 46, at the first picture, you see that snap ring with the tabs sticking up? That is what holds it in place.

When I had the driveshaft out i shined a light in the back of the T-case and the ball bearing was probobly right where the case widens out, probobly 10 inches back maybe from the outputshaft seal. but if it is not supposed to be visible maybe thats my problem. not exactly a good thing. what does the upgrade and tail houseing cost?

After trying to pin my problem to u-joints, wheel bearing, tires, I have finally found the source of my problem. Found that the bushing in the back of the Transfer Case was bad so I ordered the modified case and pump from eric at merchant. Got the case out today and got it spit to find that i had a failure and had pretty much fried the inside of the case. So now i am spending even more to get a rebuilt modified from eric. Not very good news for me, but i guess you win some and you lose some. I just cant believe that there shouldnt be a recall on this. It sounds like alot of people have pump rub or failures. I only have 75,000 miles on my truck the t-case is fried. It sucks.

I have the same vibration but only when the truck driven for an extended period of time. This happened before and after my transfer case/pump rub was fixed.
Some say it may be the tires not balanced correctly.

I wish mine would have been tires for sure, but the transfer case was toast.