Saab 9-7x stuck in AWD

Marty

Original poster
Member
May 15, 2013
11
I have a 2005 9-7x with 75,000 miles. I replaced the front driver side wheel hub bearing and now when I make slow moving tight turns the front wheels are binding in what appears due to it being stuck in AWD. It was not doing this prior to the hub bearing replacement. After researching this site I decided to change the transfer case fluid (as I bought the truck used and I am not sure if had been previously done) I used the proper Auto Trac II fluid and completed this task yesterday, I drove the truck and the problem persists. From what I have read here there is no link between the ABS sensor and the AWD so I am at a loss to figure why this occurred following the Hub change, could be purely coincidental. I have no MIL or ABS or 4 wheel lights set on the dash, I am now looking for my next step, should I replace the front differential fluid as well? should I take off the encoder motor to see if I can switch out back to rear wheel drive ( but if the motor was bad would it not set the MIL light on?)

Thanks
 

jrSS

Member
Dec 4, 2011
3,950
Probably just the switch itself. What does the switch indicate when u switch from 2 hi to 4hi etc.? With the truck off move the switch back and forth to clean contacts in the switch.
 

BO TIE SS

Member
Nov 18, 2011
1,497
Marty said:
should I replace the front differential fluid as well?
That would be my next step. Especially since you don't know the vehicle history. I would change front and rear at the same time.
 

jrSS

Member
Dec 4, 2011
3,950
Marty said:
On the 9-7x there is no switch its fully automatic AWD.

Haha. :doh: definitely something going on internally. And if u have awd....its not "stuck" in awd. Its awd no matter what. (There are threads on this topic) If ur crow hoping then something has to be wrong with the front diff. I too have awd.
 

tricguy007

Member
Dec 7, 2011
131
Check ur encoder motor on the x-case I bet its bad that is the only thing that puts the transfercase in awd mode if u pull the motor off then u can check the operation of the x-case by turning the shaft
 

Marty

Original poster
Member
May 15, 2013
11
jrSS said:
Haha. :doh: definitely something going on internally. And if u have awd....its not "stuck" in awd. Its awd no matter what. (There are threads on this topic) If ur crow hoping then something has to be wrong with the front diff. I too have awd.

I realize that AWD implies "AWD all the time" but according to the operator manual:
"All-Wheel Drive (AWD) System
Your vehicle has this feature. There is no lever or
switch to engage or disengage the front axle. It is fully
automatic and adjusts as needed for road conditions.
Your vehicle has an active transfer case allowing
two-wheel-drive operation on dry roads. The transfer
case will shift automatically into all-wheel drive on
slippery surfaces. You may feel an extra shift when the
all-wheel drive engages"

So rather than the driver of the truck a computer somewhere decides to tell that encoder motor to switch to all wheel drive.
 

BRomanJr

Member
Dec 9, 2011
371
Marty said:
I have a 2005 9-7x with 75,000 miles. I replaced the front driver side wheel hub bearing and now when I make slow moving tight turns the front wheels are binding in what appears due to it being stuck in AWD. It was not doing this prior to the hub bearing replacement. After researching this site I decided to change the transfer case fluid (as I bought the truck used and I am not sure if had been previously done) I used the proper Auto Trac II fluid and completed this task yesterday, I drove the truck and the problem persists. From what I have read here there is no link between the ABS sensor and the AWD so I am at a loss to figure why this occurred following the Hub change, could be purely coincidental. I have no MIL or ABS or 4 wheel lights set on the dash, I am now looking for my next step, should I replace the front differential fluid as well? should I take off the encoder motor to see if I can switch out back to rear wheel drive ( but if the motor was bad would it not set the MIL light on?)

Thanks

There is a link between the front ABS Sensors and A4WD/AWD systems, the front sensors are used to measure front wheel speeds and determine if the rear is losing traction.

Changing the Transfer Case Fluid is the most common fix for this problem, sometimes driving a while and doing a second change really improves the situation.

Also, I agree that checking and changing all Fluids on a proper schedule is important for all vehicles.

Finally, the Encoder can fail and removing it from the Transfer Case will expose whether it is the problem.

FYI, as I understand the system: The wet clutch to engage the front axle is spring loaded and removing the Encoder will allow it to release if the encoder is bad.
This clutch never fully releases and this is one of the reasons the Auto Trac II blue fluid with a special friction modifier is used. This friction modifier wears out (time and temperature) and hence the 50k change interval. When the friction modifier wears out it affects the TC clutch gradually as it has permeated the clutch fibers and new fluid (friction modifier) can take a while to re-permeate the clutch fibers and alleviate the binding.
 

Marty

Original poster
Member
May 15, 2013
11
tricguy007 said:
Check ur encoder motor on the x-case I bet its bad that is the only thing that puts the transfercase in awd mode if u pull the motor off then u can check the operation of the x-case by turning the shaft

As mentioned in my initial post my two possible next steps were to change out the front diff fluid which was seconded by BoTieSS and my next step was what you are suggesting. Although it appears the motor is simple enough to remove what is the home position for the shaft? is there a neutral position as well as 2 wheel and 4 wheel? Also if the encoder motor was bad would the fact that it was not moving throw a code enabling the MIL or "Service all wheel drive" light on the dash? or is it a TCCM only code that can only read by a scan tool.

Thanks for the help so far.

BRomanJr said:
There is a link between the front ABS Sensors and A4WD/AWD systems, the front sensors are used to measure front wheel speeds and determine if the rear is losing traction.

Changing the Transfer Case Fluid is the most common fix for this problem, sometimes driving a while and doing a second change really improves the situation.

Also, I agree that checking and changing all Fluids on a proper schedule is important for all vehicles.

Finally, the Encoder can fail and removing it from the Transfer Case will expose whether it is the problem.

FYI, as I understand the system: The wet clutch to engage the front axle is spring loaded and removing the Encoder will allow it to release if the encoder is bad.
This clutch never fully releases and this is one of the reasons the Auto Trac II blue fluid with a special friction modifier is used. This friction modifier wears out (time and temperature) and hence the 50k change interval. When the friction modifier wears out it affects the TC clutch gradually as it has permeated the clutch fibers and new fluid (friction modifier) can take a while to re-permeate the clutch fibers and alleviate the binding.


Thanks BRoman good stuff here, I am glad you considered the ABS sensor, it has been nagging at me. This problem started immediately after changing the Hub bearing that has the sensor as part of the assembly if the sensor is defective this could cause the issue. Can I just disconnect the sensor and see if it goes back to 2 wheel rear? I guess it will give me an ABS fault but it may clear up where the problem is.
 

BRomanJr

Member
Dec 9, 2011
371
Marty said:
Thanks BRoman good stuff here, I am glad you considered the ABS sensor, it has been nagging at me. This problem started immediately after changing the Hub bearing that has the sensor as part of the assembly if the sensor is defective this could cause the issue. Can I just disconnect the sensor and see if it goes back to 2 wheel rear? I guess it will give me an ABS fault but it may clear up where the problem is.

If the new wheel sensor was bad you would have an ABS light or ABS engagement at low speeds.

It is more likely that you noticed the binding during your hub replacement test drive and it was there before.

You can try the sensor disconnect and let us know the results.
 

Marty

Original poster
Member
May 15, 2013
11
BRomanJr said:
If the new wheel sensor was bad you would have an ABS light or ABS engagement at low speeds.

It is more likely that you noticed the binding during your hub replacement test drive and it was there before.

You can try the sensor disconnect and let us know the results.

Well I went for a short drive and it is still binding then I turned off the truck and pulled the ABS fuse and started to back out of the driveway and turned and the binding is still there. So off to my parts store to get some the differential fluid. I will lift the truck tonight and change the front diff fluid as well as pull off the encoder motor to check that out.

With respect to this being there before the hub change I am pretty sure it was not because it is quite noticable, even the wife pointed it out the very next day.
 

Marty

Original poster
Member
May 15, 2013
11
I replaced the front differential fluid last night and drove about 10 minutes and my truck is still binding on tight turns.

To summarize:
2 weeks ago I replaced the Driver side front wheel hub , the next day noticed the binding on turns.

3 days ago I replaced the fluid in the transfer case with GM Auto Trac II

Last night replaced front diff fluid with synthetic 75w90 fluid

Question how long does typically take to see results from the transfer case fluid change?

If my new hub was binding would it cause an unbalance enough to trigger the TCCM to engage the AWD? I am a cause and effect guy, the only thing that changed was that new hub then the result was being stuck in AWD the next day! I am trying to find a link because it appears to me to be related. Unless someone can clear that one up for me.

Thanks
 

BRomanJr

Member
Dec 9, 2011
371
Marty said:
I replaced the front differential fluid last night and drove about 10 minutes and my truck is still binding on tight turns.

To summarize:
2 weeks ago I replaced the Driver side front wheel hub , the next day noticed the binding on turns.

3 days ago I replaced the fluid in the transfer case with GM Auto Trac II

Last night replaced front diff fluid with synthetic 75w90 fluid

Question how long does typically take to see results from the transfer case fluid change?

If my new hub was binding would it cause an unbalance enough to trigger the TCCM to engage the AWD? I am a cause and effect guy, the only thing that changed was that new hub then the result was being stuck in AWD the next day! I am trying to find a link because it appears to me to be related. Unless someone can clear that one up for me.

Thanks

Have you tried removing the Encoder motor yet?

I don't think its a case of being stuck in AWD, if that were true tires would be scrubbing because the clutch would be locked.
You are probably experiencing the clutch shudder that is common on the A4WD TC.
The TSB for this says change the fluid twice, I usually drive a couple hundred miles between changes.
 

Marty

Original poster
Member
May 15, 2013
11
BRomanJr said:
Have you tried removing the Encoder motor yet?

I don't think its a case of being stuck in AWD, if that were true tires would be scrubbing because the clutch would be locked.
You are probably experiencing the clutch shudder that is common on the A4WD TC.
The TSB for this says change the fluid twice, I usually drive a couple hundred miles between changes.

I call it being stuck in AWD because it feels like it binds when I turn actually when I back out of my driveway and turn into the street, I can bring the truck to a stop if I turn to tight then I ease up on the wheel to allow it to move again. On the road it drives fine until I turn at a corner or try to turn into a parking spot.

I hesitated to remove the encoder motor because from reading Roadies post's it appears that if I had a problem with the encoder motor the TCCM would set the AWD service light and since no lights have been set! also if I do take it off I want to be able to bench test it so I am looking for more info on that, I would hate to take out the motor and not be able to do a basic test. The other issue is once the motor is out I now have access to the sector shaft what should I look for ? should it be easy to turn back and forth? what position should the shaft be it to disengage the front wheels. I think you mentionned it was spring loaded so I guess if I do remove the motor it should move to the 2 wheel position, if this is a home position where would the notch be positioned?

With respect to the TSB do you have the number so I can check it out, also I have not done much mileage since the transfer case fluid change so there is still hope on that front, so I will go get some more Autotrac II.

Thanks
 

BRomanJr

Member
Dec 9, 2011
371
Marty said:
I call it being stuck in AWD because it feels like it binds when I turn actually when I back out of my driveway and turn into the street, I can bring the truck to a stop if I turn to tight then I ease up on the wheel to allow it to move again. On the road it drives fine until I turn at a corner or try to turn into a parking spot.

I hesitated to remove the encoder motor because from reading Roadies post's it appears that if I had a problem with the encoder motor the TCCM would set the AWD service light and since no lights have been set! also if I do take it off I want to be able to bench test it so I am looking for more info on that, I would hate to take out the motor and not be able to do a basic test. The other issue is once the motor is out I now have access to the sector shaft what should I look for ? should it be easy to turn back and forth? what position should the shaft be it to disengage the front wheels. I think you mentionned it was spring loaded so I guess if I do remove the motor it should move to the 2 wheel position, if this is a home position where would the notch be positioned?

With respect to the TSB do you have the number so I can check it out, also I have not done much mileage since the transfer case fluid change so there is still hope on that front, so I will go get some more Autotrac II.

Thanks

If it is bound up that tight, removing the Encoder will diagnose it best. If the binding is more of a chattering then let the fluid work in first.

For AWD, the encoder is commanded to "tighten" the TC Clutch. The clutch is spring loaded so if the TC is working properly, removing the Encoder will always allow 2WD.

Once removed, the encoder should turn with a bit of resistance (no brake like the 2-speed encoder) just geared down. Unless the encoder is bound up (defective) it should be closely aligned with the TC shaft after removal.
For AWD operation, the encoder is commanded to apply the clutch and when AWD is not needed it de-energizes which allows the clutch to rotate it back to the 2WD position.

Don't have that TSB number handy, been mentioned on here, will look later. It is for the chattering problem, not full binding of the drive train like you described.
 

Marty

Original poster
Member
May 15, 2013
11
I removed the transfer case encoder motor and I think I see the light at the end of the tunnel, The motor appears jammed, once removed I am able to turn the transfer case shaft back and forth sort of between 12 and 2 o'clock position. I then tried to rotate the motor with a big screw driver inserted where the shaft of the x-fer case would be and I was not able to budge it. So with the motor removed I started up the truck and since the motor was disconnected I had the service AWD light on ( which had not occurred up to this point) I drove my truck around the block and I was no longer binding up so I was no longer in 4 wheel mode.

Obviously the next step is to order the encoder motor and hopefully that will resolve this issue.

I will update in a few days.

Thanks
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Thanks for the post. Some members report finding broken planetary gears inside, which are unrepairable. But if you take the end apart, you might find something else going on. I'd be curious either way. But the planetary reduction gear design means I don't think you can move the motor shaft backwards. But I may be wrong. Never tried it. I probably should. :wink:
 

Marty

Original poster
Member
May 15, 2013
11
I received my transfer case encoder motor and prior to installing it I disconnected the truck battery ( in case this forces the TCCM to wake up once the battery is reconnected)and installed the motor, 30 min later reconnected the battery started up the engine and no MIL or AWD fault lights ( not that I had any lights when the problem surfaced) took it for a drive and success all seems well.

Now if I want to make sure it goes into 4 wheel I have seen comments about driving on gravel, is that to make the rear wheels slip and force the TCCM to engage the front wheels?

Thanks
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Marty said:
Now if I want to make sure it goes into 4 wheel I have seen comments about driving on gravel, is that to make the rear wheels slip and force the TCCM to engage the front wheels?
Yes. You can also freeze some water in cookie sheets, put them under the rear wheels, and pull the same trick. On gravel you have to use more gas to break loose the rear end. If you have sand available, that's sometimes better and less risky for the system because you're using less power to break the tires loose. A water-soaked parking lot may also be a good skid pad. But when the system engages, it's sometimes with a jolt, and your trajectory can become.....unpredictable, let's say. :eek:
 

Marty

Original poster
Member
May 15, 2013
11
the roadie said:
Thanks for the post. Some members report finding broken planetary gears inside, which are unrepairable. But if you take the end apart, you might find something else going on. I'd be curious either way. But the planetary reduction gear design means I don't think you can move the motor shaft backwards. But I may be wrong. Never tried it. I probably should. :wink:


After reading your post (and prior to receiving my new motor) I started to sweat because I realized that due to the planetary gears that it would probably be extremely difficult to rotate the encoder motor shaft with a screw driver, even with a big one! So I decided to try a bench test of the motor I clipped 2 alligator clips on each motor wire on the connector (the 2 larger wires of the 5 are the motor wires the other 3 are the encoder leads), since it is a PWM motor I decided to just quickly make contact with my 12v power source and to my consternation the motor moved so I kept pulsing then it would no longer rotate I then reversed the polarity and pulsed again the motor then turned in the opposite direction till it reached the end of the travel and we are not talking revolutions here, the extent of the travel is probably 25-30 degrees, so this appeared to make sense to me since the shaft of the transfer case has about that much travel. So I guess my encoder was the problematic portion of my motor.

Thanks
 

Marty

Original poster
Member
May 15, 2013
11
the roadie said:
Yes. You can also freeze some water in cookie sheets, put them under the rear wheels, and pull the same trick. On gravel you have to use more gas to break loose the rear end. If you have sand available, that's sometimes better and less risky for the system because you're using less power to break the tires loose. A water-soaked parking lot may also be a good skid pad. But when the system engages, it's sometimes with a jolt, and your trajectory can become.....unpredictable, let's say. :eek:

Frozen cookie sheets now that is rich, I will try the wet road first .....but before you know it all the roads will be equivalent to the frozen cookie sheets when winter hits the great white north.
 

Beacon

Member
Mar 22, 2019
444
SouthWestern PA
Can someone "ball park" estimate what it would cost me if pay a mechanic to replace the encoder and/or encoder motor? i just test drove a 9-7, very nice vehicle, no rust 85k miles, but it has what appears to be the same issue Marty went through. and some brown tranny fluid, which is somewhat worrisome. Thanks in advance for any help
 

Mooseman

Moderator
Dec 4, 2011
25,178
Ottawa, ON
Apart from the cost of the motor itself, it's a 15 minute job. Four bolts and a connector. That's it. Recommend doing a transfer case fluid change as it was likely neglected. Do the differentials while you're at it.

Don't let brown fluid scare you too much. Check the smell and if it shifts well. If it's really burnt, you'll smell it. If it doesn't smell too nasty, a good fluid exchange and filter will likely keep it going. Mine had brown fluid when I got it. Changed the fluid and filter and that thing lasted another 150k+ km/6 years. Add an auxiliary cooler.
 
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Reactions: Beacon
Dec 5, 2011
570
Central Pennsylvania
If it's "crow hop" you're trying to cure - GM's TSB calls for TWO successive transfer case fluid changes. Use only Auto-Trak II sourced from a dealer for both changes - the fluid is not expensive ($9 a liter, maybe?). Mine were done with a few hundred miles of driving in between and cured it completely. Remember, transfer case fluid service interval is 50k miles on these.
I second everything @Mooseman said on transmission fluid. "Burnt" fluid smells "burnt". I think the transmission fluid service interval on these is 100k miles. If the fluid isn't already Dex VI, switch to it. Aux cooler will lengthen the life of the transmission by a lot.
 

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