9-7x AWD Issues

therealsethallen

therealsethallen

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Now, I know there's been a thread about this already. But It's old, didn't seem to be similar to my issues and didn't leave me anywhere but more confused.

So the issue at hand; It seems to have AWD grip when I'm doing above 25mph. But I only have RWD when I'm just starting off, even if the rear wheels spin. But there's no reaction happening. To test this, I stopped on moderately snowy unpaved hill. The rear wheels spun, and the fronts did not engage, I had to back down the hill onto dry pavement in order to get started. Now last week when I was changing my oil, I put it in drive on the lift, and the front wheels did spin, but the "Service 4WD" light came on, and went off with the next ignition cycle. Now, I figure the Transfer Case and it's associated hardware (Motor and TCCM) are okay. I'm thinking a wheel sensor perhaps, but I feel like that would set a code and my dash is clear. I'm beyond stumped about this.

What do y'all think?
 
It could still be the transfer case or encoder motor. Just because it spins with no load doesn't mean there is enough friction between the clutch plates to actually drive the front wheels when it is on the ground.

I'm not sure what conditions cause a Service 4WD light to come on, but if you can find out, it may give you a clue on the direction to go.
 
I found a Transfer Case and encoder on a Rainer at a pull-a-part relatively close to me, they offered me the motor and the TC for $250, which isn't awful. It's got about the same millage as my truck. According to my Haynes Manual, the TC isn't a really difficult job.
 
I'd start with the encoder motor first and then the TC. I doubt it's one of the speed sensors as that would throw a code. But for $250 for both, that ain't bad at all.
 
I'm insanely broke at the moment (Thank you college education), so I'm driving it as is until I have the money for a motor. I'm not going to buy a TC if I'm not going to need it.
 
No. It either works or it doesn't (i.e. fails completely). Yours seems to be working, just something like the encoder motor or TC isn't responding correctly.

Try to get that encoder motor with the understanding that if it winds up being the TC, you'll get it too.
 
Mooseman said:
No. It either works or it doesn't (i.e. fails completely). Yours seems to be working, just something like the encoder motor or TC isn't responding correctly.

Try to get that encoder motor with the understanding that if it winds up being the TC, you'll get it too.
Click to expand...

I already said to the owner of the yard "If one doesn't fix it, expect me back for the other"

A couple guys on ORTB seem to think it might be the disconecct or it's related housing. I quite literally know nothing about them.
 
The AWD GMT360s don't have a disconnect, I believe. The front axle is connected all the time.
Anyway, have you solved this? I may be in a similar situation. Waiting for my encoder motor to come and then I need to get it up and check whether my fronts still spin when not under load. I hope not :)
 
On the AWD trucks, there is no "real" disconnect but there is a housing there instead with a permanently connected disconnect. It looks exactly the same as the 4x4 version that disconnects but doesn't have the actuator motor. It can fail too.
 
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Hi all... Brand new here, but reading through and I have this EXACT SAME PROBLEM! Seems like the AWD works, then come to a stop on a snowy incline, try to go, and no front-drive... Spin away the rears till I back up and get a run.

Also, my "SERVICE STABILITRAK" light came on (on and off intermittently), and now the check engine light is on (as of today, when it snowed 15" and I got stuck). Have not pulled codes yet.

Hoping to know the results therealsethallen may have gotten with his problems/repairs???

Thanks all. Looking forward to learning more here...

BTW, mine is a 2008 9-7x... :)
 
What exactly does "Seems like the AWD works" mean? Have you seen it work with all 4 corners up or even on the road? No Service AWD light whatsoever? Transfer case fluid changed every 50k miles using Auto-Trak II only? Try and have someone with Tech II check your encoder motor if you haven't already.

The Stabilitrak light might be the steering wheel position sensor. Annoying but not a showstopper or an expensive repair. Also, as far as I know, Stabilitrak actually still works and tries to keep you in line in critical scenarios, even with this issue. I know I've read someone mention this. Someone correct me if I'm wrong.

Oh, and welcome :) :tiphat: Never enough 9-7Xers here ;)
 
I wound up replacing my transfer case with a low mile unit from a 2004 Buick Rainer. Hey presto! I have power to all four wheels again. The TC that I purchased didn't have an encoder, so I used my old one on it and it works just fine.

I can't weigh in on the Stalilitrack situation since my truck is a 2005, it doesn't have it, and I'm pretty unfamiliar with it as a whole.

I can't stress enough how good REALLY good tires are. Fortunately New England was graced with a pretty lackluster winter. I highly recommend a set of snow tires. Non-Studded if you do lots of highway driving.
 
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It wasn't difficult, however I have access to a lift. Poor maintainece (135k miles with the same fluid) lead to at least one failed clutch plate.
 
dkvasnicka said:
What exactly does "Seems like the AWD works" mean? Have you seen it work with all 4 corners up or even on the road? No Service AWD light whatsoever? Transfer case fluid changed every 50k miles using Auto-Trak II only? Try and have someone with Tech II check your encoder motor if you haven't already.

The Stabilitrak light might be the steering wheel position sensor. Annoying but not a showstopper or an expensive repair. Also, as far as I know, Stabilitrak actually still works and tries to keep you in line in critical scenarios, even with this issue. I know I've read someone mention this. Someone correct me if I'm wrong.

Oh, and welcome :smile: :tiphat: Never enough 9-7Xers here :wink:
Click to expand...

Well, through our "SNOWMAGEDDON" storm yesterday, I was driving around and I really thought the AWD was working - probably great vehicle balance with great tires (they are brand new all seasons). But, just like therealsethallen, when I came to a stop on a slight hill, no front wheel action - sit and spin the rears. Stopped to pick up the step-son at his dad's house in about 15" of fresh, wet snow - couldn't get going again. Spinning rears. Then, got stuck again near my house... UGH. No "SERCVICE AWD" light at all, but, like I mentioned, the check engine light/symbol did come on while driving yesterday.

I'm not too worried about the Stabilitrak thing either. I know that it and the AWD are two independent systems that work in conjunction with each other, just wanted to mention it here, because, well you never know what others may have run into!

The real kicker is I just bought the 9-7x from a used car dealer on Saturday, 3/19. Thus, no real maintenance records available to view. Got a call into them to see if they'll help me out, however, I seriously doubt it.
 
I'd start with looking at the encoder motor which is the usual failure point. Check the TC fluid and you should change it regardless given the unknown maintenance and it's usually neglected. In fact, change all your fluids. Then there's not much left except a total failure of the front differential (not likely) or the failure of the TC itself, like therealsethallen.
 
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Will a faulty encoder motor throw a code? I have a generic OBD II scan tool and the check engine light did come on yesterday.
 
The only time I've seen a TC code is with a high end scan tool like a Tech II or a Snap-On Solus/Verus. The readers that you'll find on the shelf at Advance Auto don't usually have that ability.
 
MountainMax said:
Well, through our "SNOWMAGEDDON" storm yesterday, I was driving around and I really thought the AWD was working - probably great vehicle balance with great tires (they are brand new all seasons).
Click to expand...
This was exactly my experience. I was absolutely positive the AWD works but it turned out it was just the combo of brand new snow tires, the limited-slip diff, very well weight balance and well tuned suspension. The truth is that we didn't have any hardcore snow in Central Europe this (hopefully) past winter. 15" would kill me too.

MountainMax said:
No "SERCVICE AWD" light at all, but, like I mentioned, the check engine light/symbol did come on while driving yesterday.
Click to expand...
I had the AWD light once but didn't manage to reproduce it. I have a new encoder motor but health & weather haven't permitted me to put it in yet.

MountainMax said:
Will a faulty encoder motor throw a code? I have a generic OBD II scan tool and the check engine light did come on yesterday.
Click to expand...
It can but it isn't in absolutely every case. What's worse is that is doesn't throw a regular ECU DTC but a TCCM code that the cheap ELM327-based readers cannot read without knowing GM-specific messages that will get you to it...
 
dkvasnicka said:
It can but it isn't in absolutely every case. What's worse is that is doesn't throw a regular ECU DTC but a TCCM code that the cheap ELM327-based readers cannot read without knowing GM-specific messages that will get you to it...
Click to expand...

Yep. Plugged in the basic code reader and got a P0430 code - TOTALLY UNRELATED!!! Starting to feel a little buyer's remorse... :faint:

Anyway, will be talking to the dealership today to see if they'll help me out at all. Wish me luck!
 
@MountainMax if you PM me your truck's VIN I can run it through Carfax.

Before doing anything I strongly recommend you change your Transfer Case fluid. This platform
has a 50k mile service interval for the transfer case. My buddy has an Envoy, he replaced everything...but never the transfer case fluid. Low and behold it was a bit low.
 
Just one correction for this thread. A service Stabiltrak light can often be a steering wheel position sensor, especially if you turn it off, wait a minute, start again and the light goes out. But if the light is on, the stability control system is disabled. It uses the ABS computer, steering wheel position sensor and yaw sensor to selectively apply brakes to one or more wheels to maintain stability but it NEEDS to know the correct position of the steering wheel in order to work. This is why I suggest stopping after a minute, shutting off the truck and then restarting, to enable the system again.

If it is the steering position sensor, you can reduce the incidents of warning lights by trying to park with the wheels straight.

What actually happens is quite straightforward. The sensor is an electro-mechanical device, and it uses a good old fashioned variable-rheostat-type contact to determine steering wheel position. The center area stays shiny because the vast majority of our driving is in this +/- 5 degrees area. Outside the area, corrosion can build up, resulting in a light and a disabled system. This is why if you stop the vehicle, wait a minute and restart, the light goes away.

A new switch will cure this (for a while.)

Or do what most of us do with 07s and above: just park straight when you can, and get used to restarting if the light comes on.
 
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Apparently, with the engine running, if you turn the key to the start position, that also resets the light.

I've been having the same issue on my Saab. I'll be trying to clean/fix the old SWPS. Seems to do it more the colder it is.
 
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Thanks for the info Chickenhawk and Mooseman.
Dropped the 9-7x off at the dealer this morning and I will let you all know what they come up with...

Oh and @therealsethallen, I have the Carfax already - thanks though!!! :)
 
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Looks like the original lube caked in there, which explains the failur . I guess you'll be hitting the yards for a good used unit and shaft . The shaft can be from any 360. There are new discos on eBay for around $200.
 
So, from what the shop is telling me, it's the 4x4 actuator/dissconnector that bolts to the diff - sealed unit, can only add lube. Yep, just over 134k miles.

@Mooseman - can you please forward me a link to what you found on ebay? Without a service manual, I'm kinda shooting in the dark as to exactly what I need. The shop wants $2200 to fix it - $1800 of that is parts alone!!! However, if I can find parts for a lot cheaper, they'll install them for me since I'm already on the hook for the labor and it's already apart.

Thanks!!!
 
$1800 for parts? Geez. They need a new crack dealer! And like I said, the shaft can be had used.
 
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@MountainMax , make sure you get the manuals from Mooseman's signature if you'll be doing maintenance on it yourself in the future.
 
Can't remember off hand but that's the case, you can use the one from a previous year. Not that much changed from year to year after '06 except maybe the fan clutch.
 
UPDATE:
So, I paid the $396 it took to actually diagnose the issue with the AWD system (as referenced above), and the dealership that I bought it from is going to make the repairs. Taking it to them tomorrow. YAY FOR ME!

Just wanna thank everyone for their input here. I will definitely be making this one of my go-to places for questions re: my 9-7x. I truly appreciate it.

And, just an FYI - I had to do this
http://gmtnation.com/forums/threads/low-oil-pressure-5-3.9687/
last night, and it worked like a charm. Don't neglect that tiny little filter and those fluid changes!!!
 
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