[kevin90lx]

New to the forum...lots of great info so far.

I picked up a 1996 outback 2.5 auto with 185k on it for pretty cheap. I am trying to work out each of its problems one at a time. Currently I am trying to figure out why the awd does not work. I have a reciept from previous owner who had a used trans installed about 20k ago.

With snow on the ground, the right front wheel just spins endlessly (just put a new set of tires on it). I know about the fuse slot under the hood-there is no fuse in it. I put one in and the fwd light on the dash came on, with no change in traction (obviously). It is now removed.

I've done some searching and haven't come up with much. I guess I am basically looking for a checklist of potential causes, ranked from most obvious (and hopefully least expensive) to least obvious.

Thanks in advance.

 

[nipper]

Do you hae a flashing transmission light on startup?

 

[kevin90lx]

no, the at temp light comes on briefly after start up and then goes out. no other lights on dash stay on.

 

[nipper]

no fwd light on on the dash ?

 

[kevin90lx]

...see first post.


there is a light, but it does not stay on. it only stays on if i put the fuse in under the hood.

 

[nipper]

...see first post.


there is a light, but it does not stay on. it only stays on if i put the fuse in under the hood.

well thats not good news.

I bet your AWD clutchpack is shot.


Either they work too well or not at all.

nipper

 

[kevin90lx]

Can someone provide a parts list for the repair? I am quite capable mechanically, although this is my first 1)Subaru and 2)AWD. Also, are the parts only available from the dealer or is there a better (read: cheaper) source?

Thanks for the responses Nipper.

 

[kevin90lx]

Ok, I did some homework and this is what I've come up with so far. The symptom is that AWD is not engaging (no power to rear wheels).

The inputs for the TCU are:
1. throttle sensor/idle switch-car runs good, no idle issues so I think this is ok
2. vehicle speed sensor #1-measure rear output shaft speed
3. vehicle speed sensor #2-measures front output shaft(s) speed
4. tachometer signal-tach works
5. inhibitor switch-haven't tested it, but don't think this is related
6. cruise control signal-works, so not related
7. ATF temp. sensor-light comes on momentarily upon start-up, so it should be working
8. 1-HOLD switch-don't have a clue what this is, don't think I have one
9. Forced FWD (via inserting fuse into socket under hood)-tried putting the fuse in and the "FWD" light came on, indication that the function is working properly

My questions are:

1. Could one bad vehicle speed sensor being bad cause the AWD not to function?(since the TCU measures the difference between the two VSS's to decide how much power to shift to the rear wheels via the duty c solenoid and the MPT clutch pack). On a related note, which VSS does the speedometer use, because I know that one is functioning properly.

2. I read that if the duty c solenoid isn't functioning properly, that the TCU will adjust to not allow AWD. The seems like it could be a cause.

3. The only other problem that would be a worn MPT clutch pack right?

Someone please correct me if I'm wrong, but it looks like these are the only three possible causes preventing AWD from functioning...?

 

[kevin90lx]

so I finally shoveled enough snow out from around the car to put a jack under it to take a peek. Turns out the rear driveshaft isn't there.

I hope someone gets a good laugh out of this.

without going any further, I feel safe assuming 1 of 2 things:

1. the car was going to be towed a long distance so some caring individual removed the driveshaft so as not to damage the AWD (what, you think I'm dreaming? me too)

2. the car started to torque bind and the easiest solution was to remove the driveshaft. it would be great if this happened early on in the torque bindedness, not so great if they waited until the clutch pack completely seized.

hopefully i can round one up at a junkyard tomorrow to see what the deal is.

Merry Christmas!

 

[plain OM]

Laughing, but also learning.

In light of the tranny having been replaced before you bought the car, did you check to see if the replacement transmission has an AWD extension, i.e, does it have a fitting at the rear for a rear driveshaft? I believe there were some Subarus around in the 90s that were available with FWD only. Okay, laugh, but . . . .

 

[nipper]

so I finally shoveled enough snow out from around the car to put a jack under it to take a peek. Turns out the rear driveshaft isn't there.

I hope someone gets a good laugh out of this.

without going any further, I feel safe assuming 1 of 2 things:

1. the car was going to be towed a long distance so some caring individual removed the driveshaft so as not to damage the AWD (what, you think I'm dreaming? me too)

2. the car started to torque bind and the easiest solution was to remove the driveshaft. it would be great if this happened early on in the torque bindedness, not so great if they waited until the clutch pack completely seized.

hopefully i can round one up at a junkyard tomorrow to see what the deal is.

Merry Christmas!

:headslap:

:jump:

:loveawd:

ok i'll add that to the trouble shooting list, but its funny.

nipper

 

[Herman Felker]

Hello all,
I have a 1996 subaru legacy outback.
My awd is not working either.

there is no fuse in the slot and there is no Torque binding sound on tight turns. when we lifted the car on jack stands and revved it out, and the rear wheels will turn slowly and can be held still by hand.

What types of things should I look for, as to what is causing only the front wheels to be powered?

I'm leaning toward bad clutch pack, but I'm dreading the cost. I have already put so much money into this car. (Jdm motor, and all the tubes.. etc...)

thanks for any insight!

 

[CNY_Dave]

Well, in nashville snow's pretty rare so unless you are off-roading you can just leave it.

Depending on the history maybe it had torque bind and someone removed the clutch pack bits.

 

[canubaru]

do you have a CEL?
a bad front VSS, speed sensor will disable the power to the rear.

or your clutch discs are worn out.

 

[nipper]

It is age, your clutch pack is tired and is slipping badly if you have no CEL

 

[plain OM]

My awd is not working either.

What symptoms do you have, and under what conditions, lead you to this conclusion?

Raising the car (all four wheels) and spinning the tires isn't necessarily a good test of the function of the AWD mechanism. The degree to which the transfer clutch is engaged is determined by a number of factors, one of which is engine torque -- greater torque leads to a higher clutch engagement pressure. When all four wheels are raised and easy to spin, the torque required is very low, so the control system doesn't detect a need to increase the clutch engagement a lot.

Ideally, the car would be placed on a 4 wheel dyno where the braking action of the machine can be used to put a load on the engine for increased torque, and then see what happens at the rear.

For most of us, the test is probably to get on a slippery, sloped, surface, try to accelerate quickly from a stop, and have observers watching the four wheels. If one or both front wheels lose traction and spin, then at least one rear wheel should be spinning as well. (This would indicate a functioning AWD.) If a front wheel is spinning while neither rear wheel is turning (assuming the car isn't moving, or isn't moving very much), then the AWD isn't delivering sufficient power to the rear drive or there's a mechanical fault in the rear. It's important to have observers who can see all the wheels -- it's quite possible for one wheel at the back to be spinning, while the other isn't turning. This is normal.

 

[nipper]

Wet grass is the best way to test the system, but it is showing enough symptons that the AWD is most likely cooked.