Bad front diff bearing

[2fast4mom]

Some of you in TN will recall that I was complaining about a "woowoowoowoo" sound coming from my GMC front end (so I thought) when I arrived in Savannah. I first heard it on highway 64 coming into McNairy county coming to this year's rally.

I figured it was a wheel or axle bearing, it was making a speed-variable-pitched "growl".

The truck only has 33K miles on it so it is still under the GM "bumper to bumper" warranty. I took it to the dealership, they kept it for 4 days and told me it is a front differential bearing that has to be ordered and then the diff rebuilt.

Hey at least it's under warranty!! 2007 GMC 1500 4x4. My 1998 GMC 1500 has a quieter drivetrain than this one, right now!!

PS Also the REAR diff has lost its paint at the bottom and appears "rusty". Overheating maybe??

 

[GotMyAlly]

What kinda fluid ya got in there?

If it's got limited slip....did you add a friction additive to the fluid?

 

[FlatOutAlly]

What kinda fluid ya got in there?

Knowing Lou, it's Merc Hi-Perf! :laughing

The rust is from the dunking in CA water and drying in CA air.

 

[2fast4mom]

Neal I've had the dealership do everything because of the warranty. THEY check the fluid levels (or at least say they do) at each recommended interval.

HECK as much as I know they got Log Cabin syrup in there!! :beer:

 

[GotMyAlly]

Most (factory) limited slip differentials use a clutch in place of the spider gears. When you change the fluid, you have to mix in a friction additive. I've intentionally left the friction additive out on some of my lease vehicles when I was using them offroad a lot because the clutches in the limited slip bite harder without the fluid, but it increases wear and tear on the clutches. I never drove mine long distances without the friction additive on the highway in the heat of the summer though. I'm just guessing here, but without that additive that would put a lot of wear on those clutches on a long haul like CA to TN and back. I would imagine the heat from those clutches would build up pretty significantly if you didnt run that friction additive on a long haul. A tell-tale sign that there is not enough or no friction additive in there is if you make a sharp turn and the outside tire barks. Like pull up to a redlight, then make a right hand turn under moderate throttle, you'll probably hear the outside tire bark.

Most synthetic fluids don't require a friction additive, but i doubt they put syn in there at the dealership.

And of course, if you got a bearing going bad....that'll cause a lotta heat too.

I run royal purple in mine and have never had a problem, even when a little water got in the diffs. But as long as yours is under warranty, i'd let em put the cheap stuff in there.

 

[2fast4mom]

Neal you're one heckuva sleuth!! Barking tire on turn....uh, ROGER! Here I thought it was just from tire wear. I got the tire pressure monitors indash so when they would chirp I'd check the pressures and they'd all be ok. So I thought

So...if the wrong fluid is in the differential(s), then it could create LOTS of extra heat....baking the paint off the rear diff and frying the bearing in the front diff...and making the outside tire chirp...Hmmm

I will metion this to the dealer next week when the parts come in....THANKS

 

[GFinch]

Lou, I wouldn't mention it, I'd just have someone put the additive in. If you keep it you'll be doing the next OH on your dime!

 

[John Richied]

Sounds to me like you drove her 33,000 miles locked in four-wheel drive. :laughing :laughing :laughing

 

[2fast4mom]

John I may be stupid but not THAT stupid. :cool

 

[RedAllison]

I didn't think GM put limited slip in the front ends, only the rears so the additive wouldn't be up front to cause any bearing problems anyway???

Gay Mans Chevy,
RA

 

[GotMyAlly]

I didn't think GM put limited slip in the front ends, only the rears so the additive wouldn't be up front to cause any bearing problems anyway???

Gay Mans Chevy,
RA

Fek if I know....won't never see a chevy or GMC in my driveway.

But what I was talking about was more in relation to the flaking paint and rust on his rear end. The front tires shouldn't be barking in corners unless you got it in 4wd or your just plain haulin butt and slidin' around corners dukes of hazard style.

 

[pickwickangler]

The front tires shouldn't be barking in corners unless you got it in 4wd or your just plain haulin butt and slidin' around corners dukes of hazard style.

That xplains why my 2 wheel drive is barkin them front tires :laughing

 

[Rookie]

also the rears have lockers in them these days and not limited slip. Lou check your build sheet if you still have it and im pretty sure it will say locking rear differential. the front im not sure on, it may say as well on build sheet. the dealer i go to for my alignment says if i want my tires to wear more evenly and truck to handle better he doesnt go by chevy specs, i thought he was full of it, but what ever he done different worked and made a big difference. also took out the squeel in the front tires when i was turning sharply. hope this is helpful

 

[CommonArcWelder]

Sounds to me like you drove her 33,000 miles locked in four-wheel drive. :laughing :laughing :laughing

Yep. My brother ruined the front diff. in his. I believe it was a 2003? Chevy 3/4 ton. He locked it in 4 wheel drive with that push button electronic B.S. and when he put it back in two wheel drive the solenoid didn't fully disengage. He always puts gearshift in neutral and then reverse and then drive to make sure it engages/disengages. GM paid for that one. Truck was out of warranty by a couple thousand miles. Keith