hi guys.
Have a noise that I thought was a u-joint. well, 1 new drive shaft later, not a u-joint. I finally had time today to jack up my truck and check it out, I took off my rear passenger wheel and caliper and rotor(I thought it might be the e-brake or a wheel bearing). The noise doesn't really start until 25 MPH and last till 40MPH. Might be above that too but I can't hear it. well when I had the truck up on stands I put it in drive and ran it up to 30, there was the noise. I rigged the accelarator to hold my speed at 30 and listened for the noise. It is not in the rear wheel/axle at all. It is coming from the transfer case to maybe the front of the t-case or the transmission. I have checked tranny fluid and t-case fluid, it is fine. No funny shifts, or slips, or vibrations, just this noise. Hard to describe noise, kinda like a rhytmic whine, not a constant whine, it happens in rhythm and gets faster as the speed gets faster till it goes away. 4wd seems to engage and disengage just fine. What do you guys think, could it be in the IWE somewhere or what? I don't know, everything is acting fine except this noise. Thanks guys.

 

Hmmm... The only thing that comes to mind is the last bearing in the trans. I have seen a few of those fail and it will cause a noise thats hard to find. Place a prybar or long screwdriver on the trans right where the t-case bolts up and put your ear to it. If you can distinctly hear the noise through the bar then its prob that bearing. The bad thing is the only way to change it is to tear down the tranny.

 

Thanks longbed. Yeah I had no clue what it was, but it is definately a noise in that area. I have an appointment with the dealership on June 4th, that is when the transimission guy comes back, he is on vacation now. But at least I know where the noise is coming from and I will mention that too him for sure. So how much labor is generally charged for changing that bearing if that is it?

 

It depends on your mileage. They may want to go ahead and do a full overhaul while it's apart. Probably about 10-12 hours.

 

check your idler pulleys and all the other pulleys on the engine

my 08 Expy was doing that same crap. A weird whine noise from idle to about 50 mph. started out quiet and went pretty loud and then just stopped...all the time.

Ended up being the idler pulley bearing was shot. Trans guy at the Dealership was sure it was the trans as well. We got lucky that an older tech heard it during the test drive (for another issue) and stopped a major repair

 

The idler pulley noise will be distinctly from under the hood but it wont hurt to check it. put a long bar on the bolt holding the pulley on and listen to the bar. Just be careful of the fan. The grooved pulley seems to be the one that fails the most.

 

I thought the same thing 70f100longbed!

the noise was coming from right under the dash in our Expy and only occurred while in gear, never in park/neutral. Convinced me it was a trans issue. The more I work on these new vehicles, the more I miss my 60's and 70's rigs. Those vehicles were just so much more honest and up front with you when something broke

 

I will check the pulleys. I was like you, since it only makes the noise in gear and not when I rev the engine I ruled that out, but I will check for sure. I changed the grooved idler pulley when I changed my serpentine belt, but it was a cheapo from advance, maybe it went bad. or it could be another pulley. I will check for sure.

 

well longbed, looks like you were right. I finally got an apt with the transmission guy at the dealership, he drove it and gave his opinion. He said he thought it was the thrust washer(service guy said bearing, print-out said washer) in the rear of the transmission. This was without me suggesting that. They said what you said, entire tranny has to be torn down to get to it, quote was $1800-2000. Ouch. I am not sure what to do. The noise is not bad, I am thinking about driving it till it goes all the way out. I assume the noise will get much louder and consistent right before it goes. A full rebuild is about 3,000, who knows the bearing might last another couple years. I don't know. really sucks though. I got my truck home right now, trying to decide what to do, I might let them fix it next week also, I don't know. Might also get a 2nd opinion. We'll see. Anyway, just updating.