1997 Bravada no 4wd

Last week with no warning the 4wd quit working. The first indication that something was wrong I parked the car on an incline. Overnight it inched forward about 20 feet from where I parked it. I tried to back an incline in a little grass and mud and the rear wheels would spin. It had never done this before. Before it would come out with no spinning at all.
I am new to this forum and am hoping it could be something other than a transfer case problem. I know it is supposed to be a full time 4wd.
Can anyone give me any indication what could be wrong. Thanks in advance for any help I can get.

Transfercase or the front driveline. Jack up the front and see if you can turn tires by hand. Look at the axleshafts and front drive shaft also.

Thanks for the reply.
Am I right in assuming that the 1997 Bravada 4wd does not have any electrical controls or actuators of any kind that would keep it from working?
Thanks again

No wrong - look under at the transfer case and you will see an encoder motor with connections and the case has speed sensors to distribute the correct torque based on slippage.

I have just returned from the Chevrolet dealer near me. They are the only ones here that works on Barvadas now.
They checked the 4wd out and told me that I had a bad right wheel speed sensor and this was causing the problem. On the rack the 4wd seems to be working. They gave me a price of $250 to fix it.

Before I go this route can anyone tell me if this could possibly be the problem?
From everything I have read on this forum and other places this should not be the problem.
Thanks in advance.

I am currently in the same situation. No 4x4 and the ABS light is on. I tried and tried to get 4x4 working with this sensor needing fixed.

Turns out my hunch was correct, I had a vacuum leak just great enough to stop the acuator from kicking in. The ABS light is still on and 4x4 works. The speed sensor needs replaced and NAPA DOES NOT carry the sensor itself. You have to buy a whole new hub assembly to get the sensor from what they claimed.

The sensor is quite easy to replace. You would just need to remove your wheel and unscrew it from the hub assembly and the location up in the engine compartment. Should be like a 20 minute job is what I am estimating.

I have just returned from the Chevrolet dealer near me. They are the only ones here that works on Barvadas now.
They checked the 4wd out and told me that I had a bad right wheel speed sensor and this was causing the problem. On the rack the 4wd seems to be working. They gave me a price of $250 to fix it.

Before I go this route can anyone tell me if this could possibly be the problem?
From everything I have read on this forum and other places this should not be the problem.
Thanks in advance.


If the speed sensor is bad it should be fixed.
But I fail to see a connection with the problem you have.
I would call for some more proper testing.
But first we need to know what transfer case you have for sure.
4472 all wheel drive or 233 push button select.
How many push buttons on dash or transfer case no off the back of it.
The 4472 is for the 96 but I have found some on a 97.
Any service transmission lights or check engine lights or abs lights on?
Any 4W shift lights on or blinking?

Thanks for the reply. There are no 4wd pushbuttons, switches or shifters at all on the dash. It takes care of itself. It probably is a 4472.
Also no warning lights are on at all.

Thanks for the reply. There are no 4wd pushbuttons, switches or shifters at all on the dash. It takes care of itself. It probably is a 4472.
Also no warning lights are on at all.

If the 4472 AWD The only thing in there that would let it go into neutral or roll in park is internal transfer case problem.
Is it holding in park now or does it still roll forward or back wards in park?
Or is 4W working now?

I don't know if it would roll backwards or not. It will creep forward on an incline. The first time I had an indication of a problem was that it crept forward over a few hours about 20 feet into the rear of my other car.
The next time I parked it there it rolled about 5 or 6 feet in less than a hour.
It never went into neutral. The 4wd did not work after this. It still is not working.
Thanks again for the reply.

I don't know if it would roll backwards or not. It will creep forward on an incline. The first time I had an indication of a problem was that it crept forward over a few hours about 20 feet into the rear of my other car.
The next time I parked it there it rolled about 5 or 6 feet in less than a hour.
It never went into neutral. The 4wd did not work after this. It still is not working.
Thanks again for the reply.


I would raise it up and block it good on jack stands and get a strap wrench or some other tool and see if the rear drive shaft will turn in park.
It does not sound like the problem but check park linkage to.
Good luck and let us know how it goes.
MT

thanks to everyone for the help.
It will be a few days before I will be able to get it fixed. I hope it will not hurt the car to drive it like it is for a few days.
I will get back to let everyone know how it came out.

Make sure the emg brake is working good.
And check transfer case fluid level.

that dealer is trying to rip you off that year bravada does not have any encoder motor or wheel sensors for the all wheel drive it has a vicous coupler filled with silicone fluid that couples the front wheels to rear wheels the only way it can fail is if that coupler leaks so don’t let the dealer fool you

My 1997 Bravada has the Borg-Warner 4472 transfer case. It has no electical componets for AWD, it's all mechanical.

Wow, be sick a few days and Bravada trouble big time.
The '91-'97 Bravada's have the viscous clutch full time AWD transfer case with no electric parts whatsoever. No AWD or 4WD lights come on because it's constantly in AWD. Add in the locking rear differential (thanks Maxwedge) and you have a pretty setup piece. I like MT2500's jack it up and check things recommend.

Hi Everyone,
I don't know what is going on but the awd is working OK now. I did nothing to it and don't understand what happened. I know it was not working for a couple weeks.
I will wait until it acts up again now. I am sure it probably will do so again.
Thanks again to everyone who replied

Wow, that's odd. You might check some fluid levels for metallic flakes after driving.