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2003 chevy trailblazer_ls
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Discussion Starter · #1 ·
As I am driving the drivers front is squealing. I thought it was the brakes that were goin but I checked them out and they look good. Both pads and rotors.

Yesterday I was driving and the TB was in 2WD, I selected 4AWD and the squeal instantly became louder. I switched it back to 2WD and the squeal became quieter.

I am thinking that it might be hub but it was replaced about a month ago.

Any ideas guys?
 

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Only thing different about A4WD, in the absence of slippage, is the front axle actuator on the passenger side is engaged, the spider gear carrier in the front diff spins in unison with both CV shafts, and there is a small amount of torque transmitted to the front driveshaft.

Squealing might be from the diff, CV bearings, CV joints themselves, or the driveshaft bearings.

If it's worse turning one way compared to the other, it points to the hub, but yours happens when it's going straight, yes?

How many miles, when was the last time you checked TC and diff fluid levels or changed them?

A dry diff could certainly do this.

You checked the brake backing plates so they're not bent toward the rotors?
 

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Discussion Starter · #3 ·
Only thing different about A4WD, in the absence of slippage, is the front axle actuator on the passenger side is engaged, the spider gear carrier in the front diff spins in unison with both CV shafts, and there is a small amount of torque transmitted to the front driveshaft.

Squealing might be from the diff, CV bearings, CV joints themselves, or the driveshaft bearings.

If it's worse turning one way compared to the other, it points to the hub, but yours happens when it's going straight, yes?

How many miles, when was the last time you checked TC and diff fluid levels or changed them?

A dry diff could certainly do this.

You checked the brake backing plates so they're not bent toward the rotors?
98, 804 KM. It happens all the time. I have never checked TC and diff fluid levels or have changed them.

I didnt check the backing plate.

I have a look on Thurs at the backing plate and also check the TC and diff fluids.
 

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And check the Owner's Manual. The TC fluid needs to be changed at 50K miles. Diffs are typically done at 100K miles, but checking the fluid level every few oil changes, especially in the front, is a great idea.
 

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Discussion Starter · #5 ·
I changed my front and rear diffs today.

The front was completely empty. As soon as I opened up the front fill plug there was metal shavings visible. took off the drain plug and nothing came out.

The rear fluid was really dirty.

Took it for a test drive and everything seems quiet now. Even when I select 4AWD.

Going to test it again tom, when the roads are quiet.
 

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This is one of those stories that will not have a happy ending. If the front diff was dry with shavings you might need to replace it in the near future.
 

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Discussion Starter · #8 ·
Well I took it out this morning. There is no squealing when it is in 2WD. When I switched to 4AWD there was no squealing but a much heavier noise. Sounds like a bad hub noise.

Any help?
 

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Discussion Starter · #11 ·
Hey roadie, just wanted to ask if u know whats happening to the TB or have any insight.

Front was completely dry, metal shavings inside, opened drain plug nothing came out. Filled it up.

The squealing is gone, but when 4AWD is selected there is a noise there.

HELP!!
 

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Discussion Starter · #12 ·
Today I went to take the TB out the garage and noticed a small puddle of fluid. Jacked up the front and the underneath was covered a bit in Diff fluid.

I think I got a leak somewhere. Gonna look at it tomorrow.
 

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Discussion Starter · #16 ·
I replaced the drivers side axle seal a couple days ago: no more leaks.

The light squealing sound in 2WD is gone.
The hi pitch squealing sound in 4AWD is gone.
No more leaks.

I still have an issue that needs to be resolved though:

I am in driving in 2WD and everything is nice and quiet. When I select 4AWD and I get up to a certain speed I can hear a rumbling sound. I switch it back to 2WD and the rumbling noise is gone.

Anybody care to chime in?
 

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Discussion Starter · #17 ·
Still having this issue, 2WD is good but when switched to 4AWD it still rumbles and yesterday I switched to 4HI and the same rumbling sound was there.

I want to get this addressed cause I dont want to drive 2WD in winter.
 

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First you say:
Front was completely dry, metal shavings inside, opened drain plug nothing came out.
and now:

Still having this issue, 2WD is good but when switched to 4AWD it still rumbles and yesterday I switched to 4HI and the same rumbling sound was there.

I want to get this addressed cause I dont want to drive 2WD in winter.
I was on a trip with very little Internet access until yesterday, but it's very, very obvious that a dry diff with metal shavings is not going to be magically healed by ANY fluid you put in. It's permanently and irredeemably damaged. It is an EX-differential. Stop experimenting with the mode switch. You need to start looking for an affordable replacement on www.car-parts.com or Ebay. That's the ONLY remedy at this point, and if you need 4WD for winter - you need to hop to it. Sorry to be harsh, but when you write the words "dry" and "shavings", the possibility of a driveway DIY repair are already gone.

If the damaged parts break, even while covered with oil, they can jam the driver's side CV shaft and cause you to steer into oncoming traffic. Being in 2WD mode does NOT eliminate this risk due to the diff design. Please don't underestimate the risk you're taking by leaving this ex-differential installed.

Here's what my broken rear diff looked like when opened up:



 

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Discussion Starter · #19 ·
Right now the funds aint that good. I just paid this years tuition for college and the parking. I am already down 4 grand. Plus new books in Sept.

I will have to start looking for either a used on new one. I dont know as yet. Is it difficult to install a differential?

If I do decide to remove 4WD and make it 2WD what would be involved in doing so?
 

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I'm very pleased with my new, stronger, EXT rear axle I picked up for $400.

Just remove both CV shafts to get the front diff to not spin. You'll need some normal tools, plus a 35mm axle nut socket, and the instructions have been posted before.
 
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