2004 Bravada stuck in AWD permanently -- FIXED

gladesteen

Well-Known Member
Monday my Bravada starting 'crow hopping' around slow corners. I've had this happen previously, but NEVER this bad. It is permanently locked in 4 low/awd low. The Bravada does not have a selector switch, its called "smart trak" and honestly, i dont like it. As i said, i've seen this before a long time ago when it was under warranty and they replaced the Encoder Motor on the transfer case. What concerns me this time, is i cannot get it to disengage.

I've done the #8 fuse, changed the front Diff and Transfer case fluid -- yes with the GM blue Trak II stuff........still wont disengage. Its nearly impossible to drive because at low speeds, it almost locks/stops in corners.

I've got a new AC Delco Encoder Motor -- freekin $300! Will install that tomorrow and have fingers crossed.

Any other suggestions?
 

Mooseman

Moderator
Yep, had that problem on the Saab. Encoder motor borked. I just pulled the motor since it's a useless system anyway.

Btw, it's not 4low. There is just 2wd and awd (4hi) when it's engaged on slippage. There is no 4low, which is available on selectable systems.
 

BRomanJr

Well-Known Member
The A4WD (SmarTrak) Transfer Case does not have a low gear at all. It binds around turns if it's locked in A4WD. Only 3 reasons I know for this to happen:
1.Encoder bad (internal corrosion causes it not to retract)
2.Transfer case bad or VERY old fluid.
3.TCCM is bad (forcing engagement, never heard of this happening)

I think you are on the right track, drive it after fully removing old decoder. (disconnecting Encoder wiring won't have an affect if Encoder is bound up) Then drive to see if the problem is gone. If so, install the new decoder and you should be happy to drive it again.

Yup, Mooseman got it, I just type a bit slower.
 
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gladesteen

Well-Known Member
Thanks guys, will let you know how it turned out. If the transfer case is seized, i may end up dumping the Bravada.........hope not, i really like it....even w 170k on the clock.

I revised the title so it does not reflect the AWD LOW/4 LOW info. I thought this
"smart trak (crap)" system was equivalent to the Trailblazers....guess not! I really would prefer to choose what mode i'm in, rather than guess.
 
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gladesteen

Well-Known Member
I think you are on the right track, drive it after fully removing old decoder. (disconnecting Encoder wiring won't have an affect if Encoder is bound up)
BRomaN / Moose,

After taking out the old encoder, could i just spin the front driveshaft to see if it disengaged from the rear? Would save alot of time from up/down off the lift.
 

Mooseman

Moderator
No because the front axles are always connected to the differential. Your disconnect is basically an "always connected" version. It's a solid piece inside. 4x4 version actually disconnects the right axle so this stops spinning the driveshaft needlessly when in 2wd. Another reason this AWD system is lame.
 

dkvasnicka

Well-Known Member
Yep, had that problem on the Saab. Encoder motor borked. I just pulled the motor since it's a useless system anyway.
Plus there is the Saab rear LSD and almost 50/50 weight distribution which themselves are things that help a lot in winter.

I think you are on the right track, drive it after fully removing old decoder. (disconnecting Encoder wiring won't have an affect if Encoder is bound up) Then drive to see if the problem is gone. If so, install the new decoder and you should be happy to drive it again.
If I understand it correctly just removing the encoder motor will solve nothing. The TC is engaged and if the motor is dead or is not present there is nothing to disengage it and it has to be done literally manually by turning the pin that the motor goes onto -- right?
 

carshinebob

Well-Known Member
the AWD transfer case is very simple. Just two gear sprockets a chain and a clutch pack. The encoder motor applies pressure to the clutch to engage the front drive. Without the encoder motor = no pressure = no front drive. ~BOB002.jpg
 
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Mooseman

Moderator
That's right. In fact, the awd's encoder motor lacks a brake to hold it in engagement therefore after the initial lockup, it just slowly disengages by itself. The 4x4 encoder motor has a brake to hold in the chosen mode.

Still say it's a lame system. I was going to switch the Saab to 4x4 with manual controls but plans have changed.
 
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gladesteen

Well-Known Member
Hi guys,

The encoder motor fixed it! Im pretty psyched to be able to turn my vehicle again without tires squealing! hahaaa...

The old encoder was seized up, we compared the spline action with old vs new motor and the old motor spline would not spin at all. The new motor spun freely.

Thanks again for the help and support!
 

02smartrak

New Member
Monday my Bravada starting 'crow hopping' around slow corners. I've had this happen previously, but NEVER this bad. It is permanently locked in 4 low/awd low. The Bravada does not have a selector switch, its called "smart trak" and honestly, i dont like it. As i said, i've seen this before a long time ago when it was under warranty and they replaced the Encoder Motor on the transfer case. What concerns me this time, is i cannot get it to disengage.

I've done the #8 fuse, changed the front Diff and Transfer case fluid -- yes with the GM blue Trak II stuff........still wont disengage. Its nearly impossible to drive because at low speeds, it almost locks/stops in corners.

I've got a new AC Delco Encoder Motor -- freekin $300! Will install that tomorrow and have fingers crossed.

Any other suggestions?
my Bravada starting 'crow hopping' around slow corners.
Good morning guys. My 2002 Bravada started doing this. When I make a tight left or right turns, it does not roll smoothly. It feels like my front wheel is locking up. But when I drive straight, its ok. Is the Encoder Motor is the problem or the Axle Disconnect?
 

Mooseman

Moderator
Likely the encoder motor is locked in the engaged position. Pull it out and it should return to normal on its own.
 

TequilaWarrior

Well-Known Member
my Bravada starting 'crow hopping' around slow corners.
Good morning guys. My 2002 Bravada started doing this. When I make a tight left or right turns, it does not roll smoothly. It feels like my front wheel is locking up. But when I drive straight, its ok. Is the Encoder Motor is the problem or the Axle Disconnect?
FIRST, change your transfer case fluid - use only GM Auto-Trak II. Drive it at least 100 miles (preferably 500 miles). Change it AGAIN - again, use only GM Auto-Trak II.
Our Tcases have a fairly small service window of 50,000 miles between fluid changes. GM has a TSB on "crow hop" specifically for this issue in AWD vehicles and the proper procedure is TWO fluid changes with driving between them. I don't remember what the actual mileage stated was but I think I drove mine around 500 miles. After the second change, never a problem again. In fact, I'm about to change my fluid this weekend. Auto-Trak II fluid should run you around $8 to $10 per liter (not quart) and should be available at any GM dealership. You'll need 2 liters per change. Don't be surprised if the parts guy insists that they're quarts - they are definitely liters no matter what they say. (The difference is only an ounce or two anyway).
 

02smartrak

New Member
I found the problem on why my front wheels are locked into full time 4WD. Of course it’s the Encoder Motor but I did a little more investigation. I took it off and open her up just to be curious. Inside the the Encoder are 4 layers of planetary gears (pic 1). I took each layer off one by one with my leatherman and inspecting each gear and plates with pins that the gears ride on. Each layer, the planetary gears gets bigger (pic2 ). As I got to the last layer, taking each gear off, I noticed the 2 gears came off WITH the pins (pic 3). And the last plate has 2 broken pins (pic 4). Under the plate has gears that rides the planetary gears and has 2 broken teeth (pic 5). The broken teeth jammed the gears. This is how I got full time 4WD. I just cleaned everything up, lubricate and I made sure that everything spins freely so I put everything back together. As I was about to put it back into the transfer case, the splines lines up one way (pic 6), so I use a big screwdriver (pic 7), loosen the 2 small screws that attaches the motor and turn the splines to line up to the transfer case. I bolt everything on , connect the wire harness and drove the car. I can feel the difference when I turn the wheel and I don’t feel the front wheel locking up. I just save myself $300.
 

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Mooseman

Moderator
Good work. When mine failed in my 9-7x, I also took it apart and saw that two of the gears had broken teeth so I had no choice but to get another encoder motor.
 

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