2wd makes a gurgle sound that disappear in A4wd

[ragingregina]

So my 2002 trailblazer with 197,777 began making noise from passengers side. It is rotational, so only when wheels r spinning. It's a wierD metallic gurgling sound. Here's the thing when I turn to A4wd it goes away.

I can hear the transfer case switching from 2hi to A4wd and again from A4wd to 4hi but nothing for 4 lo. At the actuator I hear a high pitch from 2wd to A4wd only.

Any thoughts would be appreciated. I will keep reading other posts but most seem to be about not having 4x4 and I do.

I will in the morning get TB on stands put in 2hi and trying to pinpoint the noise.

Thanks

 

[The_Roadie]

Welcome! Almost 100% chance it's a problem in the high mileage splined disconnect on the passenger side of the oil pan. GM sealed it, and they almost never last to 200K without being removed and regularly regreased.

Offroadtb.com Front Axle 4WD Disconnect

Given that it doesn't make noise in A4WD, it may be the inner intermediate shaft bearing instead of the outer CV shaft bearing. Wiggle the CV tripot housing and see if there's play in the disconnect bearing.

To switch into or out of 4LO you need to be in NEUTRAL and rolling less than 3 MPH. Park or Drive won't satisfy the interlock. To keep the transfer case and electronics working well, you need to be exercising the system every month or so, even when you don't need it to work. To make sure it will when you DO need it.

 

[ragingregina]

Ok thanks roadie. Unfortunately I took a day on a boat over looking at my tb but I will check out ur link. I was. At first thinking it sound like a bearing but did not realize how many there are. Thought it was a wheel bearing but after stopping. In A4wd I knew it wasn't.

Also if this means anything I had the inner cv joint on the passangers side replaced by a local shop 2 weeks b4 the sound and when driving around 5mph tried putting into 4lo and instrument light blinks several times the just automatically decided to stay in the last drive I had it in.

Thanks again and if it is the splinned disconnect ..... I will have to bring her to the shop!

 

[The_Roadie]

Entire replacement aftermarket CV shafts only cost $50-60. Can't imagine a shop ONLY replacing the inner CV joint and not the entire shaft. Tell me more.

There is an interlock on 4LO so you have to be coasting UNDER 3MPH and in NEUTRAL for the TCCM to allow the change. It's in the owner's manual.

 

[ragingregina]

I finally got to that. I wanted to talk to mechanic n check. So yes they replaced the entire axel. Inner and outer cv joints. Got under the truck and that inner cv was just crazy loose. I don't know how it was staying on.

And u were a right on about 4lo works fine when I do it right.

 

[ragingregina]

Mechanic said my front differential unit is gone. I experienced some hesitation and smelt something burning when I got home last night. Is this typical of the differential or splinned disconnect. Time to read some more.

 

[The_Roadie]

When was the last time the level was checked in both diffs, and what mileage was the fluid ever changed? A diff that's never been serviced is giving a lot to survive to 200K.

 

[ragingregina]

Front and rear differential were changed arouND 60,000 at 132,000 and just 3 weeks ago at 197,000. I don't use 4wd as often and don't even use it just for the sake of exercising it. If front was gone how why no noise in 4wd. Possibly 2 problems? My disconnect was bad and Idrove to long in a4wd frying my differential?

For sure thre is a ton of play above cv jt.,

 

[ragingregina]

So I called mechanic back to C what exactly they found that tells them I need differential as opposed to the disconnect. They haven't looked inside and haven't checked fluids?? can u make a true diagnosis without that?

 

[The_Roadie]

Remind me WHICH side has the wiggling inner CV joint?

 

[ragingregina]

Passangers side. Thats also where the noise is coming from in 2hi gurgleing or something is the best word I can think of. To describe it. No noise in 4wd.

 

[The_Roadie]

I thought so. That's where the splined disconnect is. $400-500 for a new assembly.

The differential is not on that side. It's sort of obvious when they look.

How competent were these mechanics? If they don't know the GMT360 platform has a splined disconnect, flee.

 

[ragingregina]

Ok thank u . I will just go ahead and buy that new. I was concerned with the diagnosis and not even cheking the fluid or peeking in the fill hole. thank for all you help and when I get it in I will update on how it works out.

One last question. What r ur thoughts on a used disconnect? Most places won't sell w/o the axel but I just got that fixed.

 

[ragingregina]

Litterally stuck in the oil pan.

Axle out dissconect is stuck after 4 hrs of hammering away nothing. I can however remove the front of the disconnect housing.
Before I crack it off leaving a chunk as I have read happening to others....

Here's my question
What would happen if I left the inner gear, (id assume broken) bearing and seal but rebuilt from there out?

I am a stay at home mom of 2 under 3 so I have little time and money but want tb up running and safe with or without 4wd.
I am not schooled in mechanics at all but am learing as I go and I am a little worried that drilling and tapping it out is over my head especially with so little time.

Any input helps. And thanks to all of you who contribute cause I have with all your help diagnosed and replaced a cooling fan clutch, struts, lower control arms, hub assemblies among others and couldn't have done it without u. Thanks

 

[ragingregina]

I took a big gamble today and it paid off. I studied the operation and function article in offroad tb and base on my symptoms and the amount of gritty nasty grease inside the housing bet that my problem was in the fork shifting. Got the housing apart exposing the inner gear, end of inner shaft and washer . I already had a replacement from the junk yard so I cracked that opened and followed the direction in that same article to rebuild. Cleaned and regreased everything put it all together and I got 2wd drive back.

4wd always worked fine just wouldn't release into 2wd. Front 2 bearings were all chewed up.

The only thing I have to add about the process is if u have a ton of play in cv housing , have someone hold the cv housing while u knock out that axel.
Add the mechanic said I needed a front differential they were all set to get a thousand bucks outta me. I paid 150 and got a new hammer pickle fork (get the fork). I did take me close to a month to fix but its done.

 

[The_Roadie]

I did take me close to a month to fix but its done.

You stuck it to the incompetent or dishonest mechanic, fixed it yourself for a huge savings, and are an inspiration to prissy owners who refuse to get their hands dirty! You rock! Thanks for the reports.

 

[kawaholic]

AWESOME!!! I LOVE reading stories like this. Good job hanging in there. Glad you got it sorted out. Gotta love a woman who's not afraid to get under her truck and get dirty to fix it!!!

 

[ragingregina]

:wootwoot:

 

[The_Roadie]

On Trailvoy, we had a member named DirtyChevyMama (DCM), but it was not because of her prowess fixing her ride and getting filthy in the process. 'nuff said.

 

[kawaholic]