Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

2002 Subaru Outback with locking differential?

When I first pull out of my driveway in the morning my Subaru behaves great. It turns well and no problems. However once I arrive at work, after 30 miles of highway driving, the car is a different story. When I pull into a parking space it is like the car is stuck in 4 wheel drive. A hard turn left or right makes it seem like the front wheels are turning together. I can hear a slight clock, clock, clock noise as the wheels turn and it takes more power to get the car to go forward. I can also hear the wheels slip on the pavement just like when I left my old Chevy Blazer in 4 wheel drive and made a sharp turn on pavement.

After a little research I think it might be the viscous coupler but I?m not positive. What do you guys think? How much is this repair and do I need to fix it? The car drives ok the only problem is making a hard turn at the end of a long drive. But is that really a problem? Am I going to do any additional damage to my car?

I did have a problem a few years ago when after about 10k miles on a new pair of Goodyear tires the car started pulling right. After an alignment it still pulled right. The tire place (Wal-Mart?boo) realized that my tires had worn to separate sizes. I assume the two different size tires could have worn out or killed my viscous coupler. Should I write Wal-Mart tire a nasty letter and demand they pay? But more importantly what do I do with my car? It has 120,000 miles and other then this is in great shape.

You can write Wal-Mart a nasty letter, but I seriously doubt that they will give you any satisfaction. All they have to do is to ask you for documentary evidence that you rotated the tires every 5k or every 7,500k (as noted in the Subaru Maintenance Schedule).

You tell us that you had a wheel alignment done, but you made no mention of rotating the tires. Without documentary evidence of proper tire rotation, you do not have a leg to stand on, legally speaking. In fact, if you did not rotate the tires on a regular basis, you are more to blame than anyone else for the uneven tire wear that led to the apparent excess wear on the viscous coupler.

I think the installation of a pair of tires instead of four matched ones may have lead to the damage. My mechanic(25 yr Subaru master tech) states a difference of more than 1/2" in circumference(distance around tire) between tires can cause AWD damage. Subaru’s official stance is 1/4". He stated a cirucmference difference he has seen of 1" has broken AWD transmission components.

Is this a manual transmission or automatic?

It wasn’t uneven tire wear, I miss spoke above, or installing an unmatched tire. I had the tires rotated regularly and probably do have that documentation. It was a actually a problem with the manufacture of the tire. As one of them wore a bit it ballooned or something. Wal-Mart evened up giving me 4 new tires and everything has been fine sense.

Anyway that was a few years ago and linking that to this problem would be difficult even though I assume they are related and I assume the tire problem eventually that problem led to my current problem.

I’d rather concentrate on the current problem of the viscous coupler if that is what it is. Do people think that is what it is? and do i need to fix it? Thanks for your response so far. It is a manual transmission.


Now that Andrew has pointed it out, I just noticed that the OP did mention the purchase of a pair of tires. Installing just two new tires could certainly have LED to subsequent problems with the viscous coupler.

the original tires I purchased were all 4 Good year tires and when the one tire had a problem they gave me another 4 for free. I did drive on the bad tire for a while before I figured out the problem. probably 5k miles.

ding ding ding! I’m also thinking that replacing two tires instead of all four could’ve very well caused the center diff to fail or at least start to fail.

So, then we should ignore what you had said in the original post…“after about 10k miles on a new pair of Goodyear tires the car started pulling right”?
I find this to be confusing.

I knew all 4 needed to replaced at the same and ensured I did that.

yes ignore that sorry for the confusion. that should have said after about 10k miles on the new 4 Goodyear tire the car started pulling right…

If you really drove 5000 miles (5k?) on a spare you may have caused some damage to your vicous coupling or rear differential. However I would start by changing the rear differential fluid and inspecting it before doing anything with the viscous coupling(center diff).

The good thing on manauls is they are much more tolerant to differences in tire circumferences vs automatics. Automatics use a different AWD system(clutch pack) in the center portion.

i just founcd your post. Hopefully by now (October) you have found the many other posts on the Web on what is definitely a Viscous Coupler problem. I have had the same issue for months, although the dealer said it was the manual transmission - wrong! - and have been putting off doing anything because of the several thousand dollar estimate to fix it. I too have your question - can I keep driving this way indefinitely. It’s annoying, but only in parking lots and my driveway! Good luck.