NEED HELP Bravada AWD not working

[Lins Bravada]

Hello,

First time posting. My wife's car, a 2002 Bravada with AWD, 4.2 liter with 190k miles on it. The AWD is not working. Only the rest wheels provide power. Initially the 'service AWD system' ligts was not on. I checked all fuses. I replaced the TCCM and had the dealer program it with the VIN. Didn't fix the problem. I then replaced the transfer case motor. That didn't fix it. Both the TCCM and tranfercase motor were bought used. M at abloss.

I'm at a loss. Any help would be much appreciated.

Thanks.

 

[smt 59]

Do you know for sure that the used parts you purchased were functional?

 

[djthumper]

Have you taken a look at the disconnect?

 

[Mooseman]

AWD don't have a "real" disco. It's an always connected type. It would still work even if the bearings in it failed but the axle would be loose.

Would probably need to get all 4 wheels in the air on a lift and see if front wheels engage or not.

How long have had this truck? Hows the maintenance? Transfer case fluid changed every 50k miles?

 

[djthumper]

They have a disconnect but internally there is a single part that makes it Full time AWD. It is subject to go bad just like a 4WD will if it isn't greased properly. http://gmtnation.com/forums/threads/gmt-360-370-awd-disconnect.14630/

 

[Lins Bravada]

Do you know for sure that the used parts you purchased were functional?

I do not know that they were functional. Bought from eBay salvage companies.

 

[Lins Bravada]

AWD don't have a "real" disco. It's an always connected type. It would still work even if the bearings in it failed but the axle would be loose.

Would probably need to get all 4 wheels in the air on a lift and see if front wheels engage or not.

How long have had this truck? Hows the maintenance? Transfer case fluid changed every 50k miles?

I got the truck a year ago from brother in law in Virginia. Probably new or rarely seen snow. I live in northern Illinois. I don't know his maintainence history with it. I'll change the transfer case flyid today. As for getting in the air, are you saying to run it in drive? And check for what/how?

 

[djthumper]

If all four wheels are in the air and you put it in drive you should see all four moving. If not you can check things out up front better

 

[Lins Bravada]

I have it in the air, spun each front wheel. They spin independently of each other. Spinning one does not cause the other to spin. There is a ticking noise coming from front hub. Not noticeable when driving. I started the car, put in drive at idle and the ticking noise at the front hub now became a loud ticking/grinding noise. When I put it in park the front end noise became a very loud grinding until the driveshaft stopped spinning. The front wheels never spun while in drive.

 

[djthumper]

It really sounds like your disconnect is toast. I know it is an AWD but here are a couple of articles that may help you.
http://www.offroadtb.com/articles/tech-docs/what-is-wrong-with-my-4wd-system/
http://www.offroadtb.com/articles/tech-docs/front-axle-4wd-disconnect/

 

[linneje]

http://www.ebay.com/itm/Trailblazer...ash=item25a200f23a:g:VokAAOSwKrhVb0lP&vxp=mtr

I think that you would save yourself a lot of hassle by just buying the whole assembly.

 

[Lins Bravada]

Update...
I took off the disconnect and found the splines on the right side of the intermediate axle shaft to be stripped to nothing. My guess is that the disconnect seized and the axle shaft was damaged. The left end of the shaft looked fine. The seal was also trashed. Pieces of the seal and spring material lying in the collar. There was nothing immediately inboard of the seal. Further in (inches) I could see bearings and the pin. Ill looked intact. I will also replace the seal. Here's my confusion...I have been all over the internet and have found nothing saying that there should be anything immediately behind the seal and if there is supposed to be any fluid/grease in where the shaft goes, as a lubricant.
Thanks all for any help.

 

[Mooseman]

This is the best article on the breakdown and rebuild of the disconnect at our brother site ORTB. Although it is primarily aimed towards the 4x4 version (which really does disconnect), it shows the solid sleeve that the AWD versions use instead of the fork and splines.

You might be able to rebuild it but if there is that much damage, it might be cheaper to try and find a good used unit along with the shaft. New ones are a bit pricey but this one seems to be the best price for new:
http://www.ebay.ca/itm/Trailblazer-...nt-axle-disconnect-assembly-NEW-/161631760954