Why does only one front tire spln in snow when crossing a highway?with a subaru forrester 2009 2.5 touring AWD

all wheel drive is not 4 wheel drive
there is a diff in the transmission that supplies power equally to the front and read wheels
when traction is lost on a drive set , the other set will remain stationary and the set without traction will spin as in your description
the same result will occur if you have both driver side wheels in a bog, the passenger wheels will be stationary and the drivers side wheels will spin
on some AWD vehicles and I thing yours has one there is a button that can be engaged that stops the transmission diff from acting like a diff and then the rear wheels will drive
read you owners hand book for driving in bad conditions

For 1999 Subaru Truck Forester AWD 2.5L MFI 4cyl the Oxygen Sensor is located under hood, center, rear engine area, mounted on catalytic converter.



Fig. Oxygen sensor location-Forester 1998-2002 2.5L SOHC engine (click over image for zoom).

Generally, Bank 1 is front and Bank 2 is rear.

Hope helps.

There are a few possibilities, The cheap is if someone was trying to save gas or tow the car, a fuse under the hood on the right side as you are sitting in the car may be installed. There may be a cover with FWD over it. when there is a fuse in here it disengages the rear wheels. The other issue could be the viscous coupling. These are a few hundred $ used and require removing the back cover of the trans to replace.

The tire size for your vehicle should be located on the driver door near the door latch.

it is usually the best way if you plan on driving on it for a while but if you are just going to repair shop to get new tire don't have to but yes disconnect awd.

This car is great in the snow. It has front wheel drive; however you should buy FOUR snow tires for safety's sake!

this transmission has a known fault with the awd section of the transmission, it is quite common to find the fuse out, because at somepoint in the life of the car an expensive repair was required and the owner did not want to do it, no fuse awd does not work end of problem. Put a fuse in, if the vehicle then judders on full lock in reverse or going forward, the fault is the awd solonoid block, depending on how long it was run in this condition, will depend on how much of a repair will be needed. Find a reliable transmission repiar shop and get a quote, not knowing were you are i cannot say with local prices how much it would cost. Hope this helps.

An addition to my previous post (after talking to my husband more). Three of our wheels were snow packed. Not the wheel wells, but the inside of the wheels. He thinks that this is what caused the problem. The ABS sensors are located there. Having them encased in snow was likely what caused this condition. Solution = clean all the snow off your tires -- and the problem should go away. Sounds like the problem is moisture gets into the ABS sensor or something shorts out with the communications to those sensors.

I have the same car. Mine is automatic. What is yours?

Possible scenarios:

1/ Is the FWD on the dash panel lit up? This will tell you that only the front wheels are engaged without power to the rear wheels. The manual tells you if you have a flat tire in your car, you have to make it into a FWD by inserting a fuse in your fuse box. Check and see if the circuitry isn't shorting out your awd which is making it fwd.

2/ Because the car has open diffs in the front and rear axles, you (or your friend) might see only the front wheels spinning and not the rear wheels. The power is transfered to the wheel with lowest resistance. With the front wheel spinning, one of the rear wheel(s) should also spin. Might not be a solution but maybe you can't see the rear spinning wheel because it's spinning on the other side.