AWD inoperative

[SVXMAN2001]

So I've been putting off dealing with grinding noise coming from the rear wheels, until now. I had posted this problem a couple of months ago and members had suggested that maybe the cause was brake binding or some sort of rubbing against something in the wheelwell.

Today, I had a chance to get the car up on 4 jack stands. I put the car in D and only the front two wheels were rotating, rear wheels were not moving at all...I have a 92 mind you. So then I put in in 1st gear and the rear wheels sporadically started to turn, mind you when they turned it was evident that the rear wheels were definately the cause of the grinding noise. to get the rear wheels to turn I actually had to rev up to about 2k rpm's to get the rear tires to turn. And once again when they did turn it was only about one or two rotations, then they would stop, and then slowly start turning again.

Also mind front passenger side wheel was spinning noticably faster than the front driver's side, what could be the cause of that?

So now having done a bit more investigation I am thinking that my problem is deeper than seized rear brakes. Could my AWD system be malfunctioning?

Couple of other things to mention I recently installed new rotors/pads on all four corners. Also when after a couple of minutes in drive, when the car is on jackstands and only the front two wheels are turning, the ABS light comes on.

Given all these additional symptoms what do you guys suggest i do? Thanks in advance.

[NiftySVX]

Originally Posted by SVXMAN2001

So I've been putting off dealing with grinding noise coming from the rear wheels, until now. I had posted this problem a couple of months ago and members had suggested that maybe the cause was brake binding or some sort of rubbing against something in the wheelwell.

Today, I had a chance to get the car up on 4 jack stands. I put the car in D and only the front two wheels were rotating, rear wheels were not moving at all...I have a 92 mind you. So then I put in in 1st gear and the rear wheels sporadically started to turn, mind you when they turned it was evident that the rear wheels were definately the cause of the grinding noise. to get the rear wheels to turn I actually had to rev up to about 2k rpm's to get the rear tires to turn. And once again when they did turn it was only about one or two rotations, then they would stop, and then slowly start turning again.

Also mind front passenger side wheel was spinning noticably faster than the front driver's side, what could be the cause of that?

So now having done a bit more investigation I am thinking that my problem is deeper than seized rear brakes. Could my AWD system be malfunctioning?

Couple of other things to mention I recently installed new rotors/pads on all four corners. Also when after a couple of minutes in drive, when the car is on jackstands and only the front two wheels are turning, the ABS light comes on.

Given all these additional symptoms what do you guys suggest i do? Thanks in advance.

The front wheels spinning at different speeds is normal, that's just the open differential up front...differential-ing. The other problem is most likely a Duty C failure. Mine did the same thing. There is an easy way to check it. Park the car over concrete in a queit area, like a garage or parking lot somewhere and turn the ignition to on (engine not running). Shift the car to neutral, then bend your head down outside the door, like you were trying to look at the undercarriage. Then, slide the shifter into a drive gear (R, D, 3, 2, 1 doesn't matter which just not p or n) and you will hear the duty c solenoid buzzing like a bee. You can move the shifter from n-d or n-r several times until you hear the noise. It stops when you go to P or N. A physically stuck solenoid will usually make a noise that is sort of like bzzzzzz....zz....zzz... and then stop, or make no noise. A healthy one should just keep going.

I've diagnosed at least 20 4EATs this way, and that is about 90% of them in the state of oklahoma, haha

As for the grinding in the rear... are you sure you haven't just lost a wheel bearing?

[SVXMAN2001]

thanks for the info, although hopefully you aren't right. I'll have to do that test you suggested.

As for whether it is a wheel bearing, definately sure that it isn't a wheel bearing, i've had enough of them gone bad in my svxes. It is much harder to physically turn the rear wheels by hand as compared to the front wheels, as if the rear wheels are locked.

[SVXMAN2001]

since i had the car up on stands already, i tried your test niftysvx. Put it into D and definately heard the distinct bzzzzzzzzzz, no interruptions it just kept going. Just to make sure I had it in D, 3,2,1 for a total of about 2-3 minutes. So hopefully I can rule out the Duty C Solenoid.

[NiftySVX]

Hmm. I would remove the rear wheels and brake rotors and inspect the parking brake assemblies, and diagnose from there in. You can turn the wheels without the brakes installed but be sure and jam a block of wood or something in the rear calipers so you don't pop the pistons out if you hit the brakes. Have you checked the fluid level and condition in the rear differential? How does the bearing(s) and u-joints look on the driveshaft? You'll also note that when turning one rear wheel by hand it is more difficult to turn than one front wheel because of the LSD effect, it will turn the other rear wheel and the driveshaft, as well as the driven plates of the transfer clutch. make sure that your new pads aren't to thick, but I am sure you would have noticed if they were because the caliper wouldn't have been able to fit over the caliper bracket with pads installed. I would also consider checking the transfer clutch pressure at the test port in the extension housing as outlined in the FSM if you have the tools to do so, but only after figuring out what is dragging on the rear drive section

[NiftySVX]

Oh, and the ABS light is because the computer doesn't see proper wheel speed from the rear sensors since the car is up in the air, this is normal and the light will go off once you drive the car and the control unit sees normal wheel speed values again.