Growl in 4wd

becks

Original poster
Member
Aug 24, 2016
10
minnesota
So my new to me 06 envoy is slowly bleeding me to death. Here's next on the docket. When I switch to 4wd I get a terrible growl from the front end. I'm pretty sure it's in 4wd but I'm afraid to drive it too far making that noise cause it's super bad sounding. When I bought it the 4wd wouldn't engage and the dealer replaced the 4wd actuator. Any troubleshooting tips? Ideas?
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
If it's coming from the front, start checking from the transfer case forward: Drive shaft/u-joints, differential, axles, disconnect, stub shaft in the oil pan. You could jack the front end and turn each wheel by hand. Another thing you could do is jack up all 4 wheels and secure on jack stands, engage 4wd and put it in drive. See if you can pinpoint where the noise is coming from.
 

becks

Original poster
Member
Aug 24, 2016
10
minnesota
if the actuator is only partially running out, would it be possible for it to make this growling noise? I read a great write up on the other site about cleaning the actuator from roadie. Is he over here now?
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
The Roadie is on an extended sabbatical so we don't hear from him anymore.

It's possibly for the disco to make noise but it would be when you have rear wheel spin and it's trying to turn the front wheels. In other words, there has to be a speed difference between the input from the front differential and the right axle. And it would be a grinding gear type of noise.
 

becks

Original poster
Member
Aug 24, 2016
10
minnesota
Ok so just FYI it's going up on jacks tonight. When it is in 4wd hi it grinds all the time. When in auto 4wd it only grinds at around 15mph and up. This is all on dry pavement so no wheel slip in auto.
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas

becks

Original poster
Member
Aug 24, 2016
10
minnesota
Are you talking about the electric actuator when you say disconnect? The actuator is brand new, the dealer installed it about 4 months ago.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
There are two parts to this. The disconnect is the mechanical part that is bolted to the oil pan and has the axle going into it. The actuator is the black plastic "motor" that is on the disconnect and actuates it.

Feb-2015-Ebay-004.JPG
 
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budwich

Member
Jun 16, 2013
2,027
kanata
sorry for bringing up an older thread but thought I would post my issue here first and go from there.

2008 TB 4.2. Being summer, it is running in 2w drive (actually don't used the 4WD much... just going up oil change ramp and winter ice driveway type effort). Its got about 230Kkm... bought used at about 130Kkm. Anyways, going down the road is basically smooth in terms of roll but at about 20 mph, its starts to growl in the front and gets louder with speed. Doesn't appear to notice much change in cornering at speed although I haven't really cranked in any direction at speed ... no sense adding a rollover to my problem... :smile:

I haven't inspected things yet but was wondering the most likely candidate to check.... hub, cv joint, others? Not totally familiar with this setup as this is my first 4wd that I have owned. Transfer case fluid was changed when I got it and was changed again recently.
 

HARDTRAILZ

Moderator
Nov 18, 2011
49,665
I would start with hubs. Jacked it up and give them a spin and shake and see what you find.
 

mrrsm

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Oct 22, 2015
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If needed...

 

Mektek

Member
May 2, 2017
656
FL
Had the same problem and initially blamed the 4wd system. There was a bad seal that let most of the front differential oil leak out to the bottom of the axle so I thought that maybe that caused damage.
When I started to hear the growl I made abrupt turns in both directions and found that the pitch of the sound changed slightly when I turned right.
Ordered a hub from fleabay and replaced the left hub. And the growling was gone!
When I pressed apart the hub I found damage in the outer race, which is induction hardened and machined out of the hub itself. The inner bearing and race was OK.
At 230K if the hubs are original then that could be near the end for them. Strangely enough I had more wear on the driver side suspension components than the passenger side...
 

budwich

Member
Jun 16, 2013
2,027
kanata
thanks... time to do some "jacking up"... :smile: related to your post of the "fleabay hub", I have seen some discussion about various makes... the gm ones seem rather expensive compared to the "non oem", is yours holding out? I figure there are a couple of rocka ones in my price range... :smile:

thanks for the video link... definitely a doable job... let's hope I find the right unit at fault and don't have to dig deeper.
 
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Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
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budwich

Member
Jun 16, 2013
2,027
kanata
went for a spin around the "freeway / exit ramps". It would appear that 40-50 mph turn to the right reduces the noise while an equivalent left turn has no impact on the sound. I would take this as the problem on the right side (ie. weight has move off that drive unit). I will focus there first.
Found a canadian ebay listing for a pair of 513188's... asking the seller what make as this appears to be timken / moog listing but the price for the pair is under $100.

I see that it is a "generic number" for the unit so based on this it is likely a power stop make.
 

budwich

Member
Jun 16, 2013
2,027
kanata
Jack up the right side (haven't done the left yet). spin the wheel and could hear a what appear to be light low "rumble" noise as compared to perhaps the pads slighting over the disc. It wasn't continuous noise.

Yesterday, immediately after my "freeway test", I shot both sides with my "low res" hand held thermal imager... might as well use it, I paid for it... :smile:

RE-EDIT:
Anyways, it appear to show a slight difference BUT the difference appears to be showing the left hotter than the right even though the exhaust is on the right. I guess I need to do more "jacking".

maybe the noise that I hear on that side is indeed the disc rubbing as the rotor appears to show more heat (although there is some time difference between the pictures).
 

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budwich

Member
Jun 16, 2013
2,027
kanata
A quick "jack up" indeed does show looseness on the left side. :-( ... :smile: good that I think I found the issue. Now all I have to do is get the parts and replace at least that one (and maybe do them both since it might be past their time).
 

Mektek

Member
May 2, 2017
656
FL
I doubt AC delco is actually making hubs anymore as the platform is long out of production. What you'll pay extra for is the nice blue and white label on the box.
I doubt that timken makes hubs either. You might get their bearings used in the hub, but that's the extent of their contribution. The outer bearing race is the same induction hardened item used in any brand. That's why they can fail quickly - it's a very complex and precise procedure to harden the race after machining and any imperfection soon becomes evident.
The low cost fleabay units are so far OK after nearly a year. The real test will be on a upcoming 5000mi roadtrip.
 
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budwich

Member
Jun 16, 2013
2,027
kanata
thanks for the info. I will likely give the "2 for $95C" a try as I am somewhat a "pig iron is pig iron" kind of guy (the gm exhaust replacement manifold only lasted 3 years, now went with the non-oem, 1/2 price... can't be any worse) although asking the seller a question about the 513188 reference on his ad with his response "we use aftermarket parts and numbers as references" without him actually stating what the "real make" of the part was kind of leaves a "what's up".
 

budwich

Member
Jun 16, 2013
2,027
kanata
wow... I did the ebay buy thing (supplies core) this morning and they showed up at my door just now... this is in canada on a sunday. Holy smokes. Now I need to get to CT and borrow the 35mm socket for the axle nut.
 

budwich

Member
Jun 16, 2013
2,027
kanata
well, after changing out the left hub, I have done nothing. Still noise from somewhere, not quite as loud. The "movement" on the left appears to be coming from the tie rod end...:-( I hate "onions"...:smile: On to the right side side... pulled the right, the inner bearing ring fell off so now it is obvious. I guess the "corner test" was actually correct with the weight coming off the right wheel when turning right... means that bearing was being slightly deloaded and less noise.
Hopefully when I get things back together, it will be quiet. Ordered a rotor as the inside surface on the old one was indeed rusted badly cause a drag and heat as shown in the thermal picture.
 
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mrrsm

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You should consider that whenever changing Brake Parts... Do so as PAIRS and also replace the opposing side with a "Brand New Platter".
 

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