• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

Noisy Front End?


Full Member
May 7, 2002
Boise, Idaho
First post and all here. Love the forums. Have had my Avalanche now for a month and have just developed a sound coming from the front end...sounds like a throbbing sound that becomes more pronounced as I slow down. At 35 and up it smooths out into a whirring sound. Any thoughts? I'm thinking front differential as braking has no effect.
I don't have an answer for you, but this might be a chance for someone to educate us on the workings of the front transfer case. Is it actually always turning and only locked to the drive axles when in 4 wheel drive? I am a newbie on the working of how this all works.
Hi Skaneid,
There have been a relative few issues with some of the axles with bad pinion seals, gears, bearings. The symptoms sound like what you are experiencing. Check out a previous thread I posted in:

Ahhnuld said:
Alrighty then! I originally posted this thread, and since then, the noise coming from my front axle has grown louder. I dropped off the Av at a dealer for a water leak issue, and I asked them to take a spin to hear the noise when 4x4 is engaged. Lo and behold, I got call from the service advisor stating that they are replacing the pinion gear in the front axle. See the below quote from another thread titled "Pulling/Vibration":
Looks like this issue can be with either axle. I wanted to post this so ya'll will know the issue is related to the above posted thread.
on Mar 18th, 2002, 4:44pm, idocpilk wrote:Well, things are much better. ?The ring and pinion gears must have taken 1/2 a day as they spent the rest of the day on the vibration and pulling. ?The noise is gone so that must have been it. ?I still think I have a vibration problem but now it seems to be a 65 mph. ?Feels like a bad tire to me and when they balanced the tires one had 6" of balance weights...I think that tire is bad or the ?wheel is bad. ?If I still sense the vibration next week I am going to have them ?check the drive shaft and then if that's ok then I am going to ask for a new tire or wheel. ?Otherwise I am enjoying the AV a great deal. ?Only problem is I miss my old truck...I haven't got the nerve to really use this one. ?Oh well. ? ?

Hope this helps, also, are you sure its not your tires?
Well, I've checked it out in all possible gear and drive settings...does it the same in 4wd as in 2wd. Have an appointment with the local dealer to have it checked on Wednesday, so I'll keep y'all posted as things develop. Has gotten progressively worse since last Wednesday when I first noticed it.
:eek: Update # 1...

Took my AV into Edmark Chevrolet in Nampa, ID for service at 7:45 this morning. Best I've ever been treated. Service tech hopped right in and we went for a ride. Before we got out of the parking lot he asked, "Is that the noise?" It was. Did a few more turns and stops and he was satisfied. Left it and took their shuttle back to my office (free cookies, sodas and coffee while waiting). Got a call about 3pm...was an axle bearing in the front differential...frozen completely solid. Tech tells me they have the parts and are putting it back together and that he will call when ready.

An hour later he calls...good news and bad news...good news is that it's back together...bad news is its still making the noise. He said they were tearing it back down as we spoke but that it probably wouldn't be finished tonight. Asked if I needed a ride to work in the morning. Pretty fair treatment by my book.

On a different note...before I left, I did tell the tech that I had put a K&N air filter in...he asked if I had noticed any difference. I told him a minor improvement in mileage and in midrange performance. He asked if I was going to put in a FIPK. I told him I had thought about it, but wasn't sure what the service guys would think...he laughed and said that they'd install it for me if I wanted them too...seems the Service Manager has a Silverado with the 5.3 and put one in...and LOVES it. Maybe I'll take them up on the offer when I save up my $$.

More to follow as the story develops. Need the AV back by tomorrow night to go get a refrigerator.
:eek: Update #2

Service department called me this morning. Seems the differential carrier was not machined properly, allowing the axle to have too much play, eating the bearing. Still trying to figure that one out, but it sounds good.

They are overnighting the part in, so hopefully I'll see my AV before the weekend. Guess I'll have to get Dad's Dodge to haul the fridge tonight!

Good luck Skan....seems as if the dealership is being real cooperative....see if you can get a loaner car from them...something in the neighborhood of a corvette or z28 camaro..... :B:
:love: Got my truck back this afternoon. All better now.

Evidently there is a clip that positions the stub axle in relation to the axle bearing. That clip is either weak or defective, and if it fails, the inner end of the stub axle starts to "wander". This eats the bearing first, then the differential carrier assembly, then the ring and pinion gear, then, eventually, the differential casing.

No TSB out on it yet, but GM Tech Assistance evidently knows of this. I'll know more when I get copies of all the paperwork detailing all the parts replaced (they weren't done writing up their portion yet, but I needed the truck to haul the aforementioned refrigerator - the beer was getting warm!)

More to follow as things develop. My highest recommendation to anyone to go to Edmark GM in Nampa Idaho...good folks! :B: :B: :B: :B: :B:

OK, final post here on this topic (I hope, knock on wood, etc).

Here's exactly what the service department wrote up on the invoice for my AV:

Lift the vehicle and ran on the lift. The LH drive asle was wobbling up and down while the vehicle was in two wheel drive. The reason for the move in the axle was in the diff. I removed the diff. and disassembled and inspected. Found the carrier housing had been mismachined and was causing the spider gear for the LH axle to move up and down as the carrier was spinning around the stationary spider gear. The movement of the axle shaft up and down also ruined the LH axle bearing. Replaced diff. carrier and axle bearing. While I had the diff. out I removed the LH axle seal to inspect the lock tang for the bearing adj. and found the tang was broke dur to factory misaligning it when they installed it. I replaced lock tang and LH axle seal. reinstalled diff. asmb. and test drove. found another noise coming from the LH front wheel area. Lifted vehicle and ran in 4x4 and found the bearing in the LH wheel hub was rough sounding. R&R LH wheel hub and test drove to verify repair. Everything checked out OK.

Nothing but kudos to the Service Staff at Edmark. Took it for a long drive today and it sounded and handled great.

:8: :8: :C: :D: yes!!! front diff good call. can you say flaw!!!!!!!!!!!!!!! :8: :9: