[robandzoe]

Have a 99 SUS that we bought for my son's first car. In the snow, it's not AWD. The FWD fuse is NOT installed. No lights on. Just no power to the rear end. Drive shaft is installed. Anything you can help with the trouble shooting? Tonight we put it up on my mechanics lift and drive shaft present. When you spin rear wheels with the vehicle off, the drive shaft spins, but if I grab the shaft, you can still spin the wheels and hold the shaft still. We put the car into drive while on the lift and only the front wheels spun (nothing in the rear). Any help would be great!!

Thanks!

 

[eagleeye]

automatic or manual?

and under your name it says this is a 96, but in your text a 99....(not the same).

 

[robandzoe]

1999 - I'll update that - I used to have a 96.. now we have the 99. Automatic. Has the 2.5L.

 

[plain OM]

. . . Tonight we put it up on my mechanics lift and drive shaft present. When you spin rear wheels with the vehicle off, the drive shaft spins, but if I grab the shaft, you can still spin the wheels and hold the shaft still.

That's odd.

Fundamentally, with that rear differential design, if the rear drive shaft is prevented from turning, then it should be impossible to turn both rear wheels in the same direction at the same time. And, if only one wheel is turned, the other should turn the same amount (revolutions) but in the opposite direction.

When the propeller shaft was being prevented from turning, were both rear wheels being turned, together, in the same direction? Or was just one wheel being turned and, if so, did the other wheel turn? If it did turn, was it in the same, or opposite, direction?

(Possibilities, depending on more details about the test: Broken CV joint in a rear axle, or an axle stub pulled out of the differential just enough to not engage the splines.)

 

[eagleeye]

is there plenty of front and rear diff lubes in the reservoirs? (I wonder if it would be possible to put lube in that is too thick, or too thin on one end of the car).

ATF still nice looking and full?

_____

when you make slow figure 8s do you hear any growling? (= torque bind,...and I wonder if it is possible to wear something past the point that anything would "bind" anymore).

how do the tires look: All the same make and model and wear?

2 new? All new?

(I think I would prefer 4 old tires on a used subaru,...so I can see how they have worn, and buy my own).

 

[robandzoe]

We'll have to re-test it... when we turned the rear wheels while up in the air, one turned one way while the other spun in the opposite direction. If I recall correctly, when I grabbed the driveshaft and turned the passenger side rear wheel (while holding the drive shaft still), I don't think the other wheel turned at all (this was when the vehicle was in park). But while in the air, with the engine running and put into drive, the front's spun but not the back.

 

[eagleeye]

and for everyone to recall, I don't think the 1999 Sport Utility Sedan, had a limited slip rear. (despite it being loaded with other stuff).

(such popped up in US spec 2000 in the leather limiteds, and the cloth "winter/ ~All weather" package outbacks.).

Everything Subaru Outback Archives 1998-1999: options, prices, history.

edit: @plain OM. (I don't know if your previous statement reflects NO limited slip..?

 

[plain OM]

. . . when I grabbed the driveshaft and turned the passenger side rear wheel (while holding the drive shaft still), I don't think the other wheel turned at all (this was when the vehicle was in park).

Park doesn't affect the rear wheels, only the front. With the engine off, the car in Park, and the parking brake off, the rear drive shaft and wheels are free to turn. That's because the AWD transfer clutch isn't getting any hydraulic pressure from the transmission fluid pump. So the rear drive train is disconnected from the output of the transmission.

Another test (in addition to the ones mentioned in my previous post) would be to prevent the drive shaft and one rear wheel from turning, and then see if the other rear wheel can be turned. (Will require more than one person.)

If there really is no mechanical problem in the rear drive train, then the AWD transfer clutch might not be getting hydraulic pressure due to a failed control valve, or, the clutch plates are worn out. The latter can happen, fairly quickly, if the car is towed with two wheels (both fronts or both rears) raised, while the other two are on the ground and turning. AWD's need to be carried on a flatbed.

Another problem could be a fault in the wiring from the TCM to the AWD control solenoid. This should cause a trouble code and a flashing AT Oil Temp light in the dash when the key is first turned on. But that depends on the bulb being good. If it's burned out, there's no way to know there's a fault. I'm not familiar with that generation, but in later years, when the key is turned to ON but not to Start, several warning lights should come on to verify that they work, including the AT Oil Temp light and the Check Engine light. If it's the same for the 1999, do the lights work?

 

[plain OM]

and for everyone to recall, I don't think the 1999 Sport Utility Sedan, had a limited slip rear. (despite it being loaded with other stuff). . . . .
edit: @plain OM. (I don't know if your previous statement reflects NO limited slip..?

Works with either, except, with LSD, if the drive shaft is held, it's much harder to turn one wheel (while the other turns in the opposite direction). However, the fundamental mechanical principles of the three-point open differential still apply. The LSD viscous coupler, if it's still intact, will cause drag due to residual friction, e.g., of the rubber seals, but because the rate of rotation is quite slow, the viscous fluid control aspect should not activate.

 

[idosubaru]

First thing I would do is disconnect the TCM and drive it. This will force it into "locked" 4WD and 3rd gear. Don't drive it like this routinely, but just as a test to see if you now have 4WD. Drive in circles on a dry pavement turning the wheel to full lock and see if you get binding which indicates the 4WD is "locked" as it should be in this condition.

A few more basic questions:
1. Does the AT light work?
2. Does the FWD fuse light work?
3. What happens if you install the FWD fuse - does the light on the dash light up?

May have a sheared shaft/gear that drives the clutches.

 

[RoughDiamond]

Does the AT TEMP light flash upon start-up? If so, you have a fault code that may lead to the problem.

Your rear shaft will spin independently from the transmission (or front wheels) with the car off or in park/neutral. The rear shaft is only "powered" after commanded by the TCU and fluid pressure applied to the clutch pack in the tail housing. In gear (and all 4 off the ground), the rear shaft should spin and the rear wheel(s) should spin at the same speed as the front.

As to why yours isn't working: Assuming no electrical faults (no stored codes), and correct trans fluid level, you may have a stuck "duty C" solenoid or a burned-out transfer clutch pack. This is usually caused by low fluid or dissimilar tire size over a long period.

 

[idosubaru]

Does the AT TEMP light flash upon start-up?

No lights on.

Next step as indicated in my last post is to make sure the FWD and AT light bulbs are functional/working.

 

[RoughDiamond]

Next step as indicated in my last post is to make sure the FWD and AT light bulbs are functional/working.

Sometimes you've got to ask the literal to discover the truth. It's like trying to program a computer with some owners... then you get the "oh, well you didn't ask me THAT way..."