Bravada not engauging 4wd

boysatt · 12-01-2007, 12:57 PM

Well Its snowing like hell here and my mom just took her new bravada out for its first trip in the snow. Right away we figured something is wrong because it is only running rwd and not locking in the front wheels. Its a 2000 Bravada with 100K on it, she traded her 99 for it like 3 months ago since it had a lot less miles.

Any ideas where to start looking, the service awd light is not on, so I have no idea where to start. Is it possible to check the system with a computer scanner?

Mike

boysatt · 12-01-2007, 07:47 PM

I figured I would ad a update that I put it on a scanner this afternoon and for some reason it was not able to read the awd computer, maybe the ststem has a issue, but I should have been able to access it with a scanner.

Goran · 12-05-2007, 12:50 PM

did you check your fuses?

Tim99Zr2 · 12-05-2007, 12:54 PM

prob. your vacuum acuator (spelling) under the battery.

Mr Bravada · 12-07-2007, 01:26 AM

i had the same problem a couple years.....

transfer case encoder motor

dillon_b12 · 12-07-2007, 01:40 AM

Encoder motor and vacuum actuator are two VERY common problems on these trucks.

95 S_Trucker · 12-07-2007, 06:54 PM

doesnt the bravada have AWD instead of 4WD?

greencactus3 · 12-07-2007, 08:07 PM

Quote: Originally Posted by 95 S_Trucker

doesnt the bravada have AWD instead of 4WD?

thats waht i thought....
which means if the rear starts to slip, itll slip forever

Mr Bravada · 12-14-2007, 12:16 AM

i've been there..... it was funny to see it not grabbing snow at all.....

gchemist · 12-17-2007, 09:45 PM

http://www.4x4posi-lok.com/faq.html

boysatt · 01-04-2008, 02:34 PM

I figured I would post a update since I fixed the problem. First I tried to put a scanner on it and could not make connection with the awd ECU, found the power connector had corroded and burnt the connector. Fixed that and got the computer responding. Drive it a few days and no change and no codes yet. Put it on a lift and started checking things, the awd system consists of 2 speed sensors to control the actuator motor, when the front wheels slip a little, the motor will engage the case. I took the actuator motor off and bench tested it and it was good, then I manually locked the transfer case into 4wd and although it was hard to turn the front drive shaft the opposite direction as the rear, it would turn. Talked to a tranny shop and he said the clutches in it are most likely shot. Pulled the t-case, took a little over a hour, and brought it to the tranny shop. Took 2 hours and $167 in parts from the local dealer to rebuild it, he charged me $100 to do it, so for less than $300 I had the case rebuilt. And to think the dealer quoted $1400 when I called them.

Took a little over a hour to have the case back in and the car out for a drive. AWD works flawlessly. Cause of my problem was contaminated fluid that cause the clutches to slip and burn out.

Not to anyone who has theses trucks, they use special transfer case fluid and using the wrong stuff will cause it to fail, do not use ATF EVER.

Dealer also recommended changing the transfer case fluid ever 20K to prevent the clutches from wearing too fast.

Mike

12-01-2007, 12:57 PM	#1
boysatt Registered User Join Date: Apr 2006 Posts: 12 Location: User is: OffLine	Bravada not engauging 4wd Well Its snowing like hell here and my mom just took her new bravada out for its first trip in the snow. Right away we figured something is wrong because it is only running rwd and not locking in the front wheels. Its a 2000 Bravada with 100K on it, she traded her 99 for it like 3 months ago since it had a lot less miles. Any ideas where to start looking, the service awd light is not on, so I have no idea where to start. Is it possible to check the system with a computer scanner? Mike
	[Reply w/Quote]

12-01-2007, 07:47 PM	#2
boysatt Registered User Join Date: Apr 2006 Posts: 12 Location: User is: OffLine	Re: Bravada not engauging 4wd I figured I would ad a update that I put it on a scanner this afternoon and for some reason it was not able to read the awd computer, maybe the ststem has a issue, but I should have been able to access it with a scanner.
	[Reply w/Quote]

12-05-2007, 12:50 PM	#3
Goran Registered User Join Date: Apr 2006 Posts: 191 Location: Ontario User is: OffLine	Re: Bravada not engauging 4wd did you check your fuses?
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12-05-2007, 12:54 PM	#4
Tim99Zr2 Fvck New Jersey Age: 21 Join Date: Mar 2007 Posts: 7,535 Location: Reynoldsville, PA User is: OffLine	Re: Bravada not engauging 4wd prob. your vacuum acuator (spelling) under the battery.
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12-07-2007, 01:26 AM	#5
Mr Bravada graduated!!!! Age: 27 Join Date: May 2005 Posts: 1,045 Location: Anchorage Ak User is: OffLine	Re: Bravada not engauging 4wd i had the same problem a couple years..... transfer case encoder motor Last edited by Mr Bravada : 12-07-2007 at 01:28 AM.
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12-07-2007, 01:40 AM	#6
dillon_b12 Registered User Age: 23 Join Date: Oct 2002 Posts: 4,254 Location: Kentucky User is: OffLine	Re: Bravada not engauging 4wd Encoder motor and vacuum actuator are two VERY common problems on these trucks.
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12-07-2007, 06:54 PM	#7
95 S_Trucker no longer has a 95 Age: 20 Join Date: Jan 2007 Posts: 1,715 Location: Lancaster, PA User is: OffLine	Re: Bravada not engauging 4wd doesnt the bravada have AWD instead of 4WD?
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12-07-2007, 08:07 PM	#8
greencactus3 bellcranks no more Age: 22 Join Date: Nov 2005 Posts: 23,488 Location: ann arbor, mi User is: OffLine	Re: Bravada not engauging 4wd Quote: Originally Posted by 95 S_Trucker doesnt the bravada have AWD instead of 4WD? thats waht i thought.... which means if the rear starts to slip, itll slip forever
	[Reply w/Quote]

12-14-2007, 12:16 AM	#9
Mr Bravada graduated!!!! Age: 27 Join Date: May 2005 Posts: 1,045 Location: Anchorage Ak User is: OffLine	Re: Bravada not engauging 4wd i've been there..... it was funny to see it not grabbing snow at all.....
	[Reply w/Quote]

12-17-2007, 09:45 PM	#10
gchemist Registered User Join Date: May 2006 Posts: 356 Location: Austin User is: OffLine	Re: Bravada not engauging 4wd http://www.4x4posi-lok.com/faq.html
	[Reply w/Quote]

01-04-2008, 02:34 PM	#11
boysatt Registered User Join Date: Apr 2006 Posts: 12 Location: User is: OffLine	Re: Bravada not engauging 4wd I figured I would post a update since I fixed the problem. First I tried to put a scanner on it and could not make connection with the awd ECU, found the power connector had corroded and burnt the connector. Fixed that and got the computer responding. Drive it a few days and no change and no codes yet. Put it on a lift and started checking things, the awd system consists of 2 speed sensors to control the actuator motor, when the front wheels slip a little, the motor will engage the case. I took the actuator motor off and bench tested it and it was good, then I manually locked the transfer case into 4wd and although it was hard to turn the front drive shaft the opposite direction as the rear, it would turn. Talked to a tranny shop and he said the clutches in it are most likely shot. Pulled the t-case, took a little over a hour, and brought it to the tranny shop. Took 2 hours and $167 in parts from the local dealer to rebuild it, he charged me $100 to do it, so for less than $300 I had the case rebuilt. And to think the dealer quoted $1400 when I called them. Took a little over a hour to have the case back in and the car out for a drive. AWD works flawlessly. Cause of my problem was contaminated fluid that cause the clutches to slip and burn out. Not to anyone who has theses trucks, they use special transfer case fluid and using the wrong stuff will cause it to fail, do not use ATF EVER. Dealer also recommended changing the transfer case fluid ever 20K to prevent the clutches from wearing too fast. Mike
	[Reply w/Quote]