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2003 Subaru Outback manual transmission failure


I have a 2003 Subaru Outback with 5-speed manual transmission and 133k. A couple of months ago, I noticed the drive train seemed to be louder than usual but didn’t notice any performance issues.

A couple of weeks ago, I was making a rather tight left turn at about 20 mph and heard a knock in the front right area. As I drove home, the knock would intermittently recur as I accelerated.

I took it in to my mechanic, and he told me I had a transmission problem. He sent me to a transmission specialist who charged me $389 to open it up and take a look.

After a week, I was told I had a differential and transaxle problem that will cost $3500 to repair using salvaged parts. (New parts from Subaru would allegedly cost $3700 not including labor.)

Does this sound like anything you’ve ever heard before with a 2003 Outback? The cost seems very high to me.

I appreciate any thoughts you may have. Thanks :slight_smile: michael

Have you (or a previous owner) ever run the car for more than a short distance with mis-matched tires? I ask because mis-matched tires are a prime cause of transaxle and transmission problems with Subarus. The cost of running with mis-matched tires can be substantial.

Very interesting. Indeed, I replaced the front two tires about 8 months ago. (I drove about 10k during that time.) They were also Good Year but not exactly the same model. However, my mechanic said the tread patterns were the same, and it wouldn’t be a issue. I now have Good Year Assurance all around, but for that 8-month period, I had Good Year Infinity for the rear tires. Could that be the explanation? Thanks… michael

my mechanic said the tread patterns were the same, and it wouldn’t be a issue.

Sorry, but it is not the tread pattern that causes the problem. It is the diameter of the tyre. AWD does not do well when one wheel is turning more times than the other. Tread pattern (and a few other factors) can indeed cause problems, but not the one you are apparently experiencing. The miss matched tyre tread design can cause safety issues and perhaps that was what your mechanic was thinking of. Of the two it is the more important one.

For example, with 16 inch tires and driving 60 mph, your tire will rotate about 21 times per second. If one tire is new and another tire is worn down by 4/16, that worn tire will rotate at 22 times per second. That mismatch messes up transmission if it goes on long enough.

Is it safe to say running the two different kinds of tires for 10k has caused the transmission failure? It seems the tire shop should have known about this potential problem. Thanks… michael

Mis-matched in terms of tire model/tread design can be problematic.
However, mis-matched tires in terms of different amounts of tread wear is EXTREMELY problematic–especially if this situation persisted for 8 months/10k miles.

When you replaced just the two front tires, you most likely had rear tires with a fairly significant amount of wear on them, while the fronts were brand new. That type of mis-match makes the center viscous coupler/differential work overtime, and in addition to doing damage to that component, it causes damage to the transmission/transaxle.

It sounds to me like you shot yourself in the foot, although your mechanic deserves much of the blame. When you get a chance, take out your Owner’s Manual, and you will see that it advises against doing what took place on your car for 10k miles.

I am a long-time Subaru owner, and I would never take my car to a mechanic who was not very familiar with Subarus. Your mechanic clearly lacks Subaru-specific knowledge. And, since this same type of tire mis-match would be equally damaging to many other brands of AWD vehicle, it sounds like he would not be a good mechanic to patronize with any type of AWD vehicle.

Edited to add:
Yes, a tire shop should be familiar with this issue, as should your mechanic.
It sounds like you have two establishments to avoid in the future.

I used “tire shop” and “mechanic” interchangeably. I’ve been taking the car there for routine maintenance for the past 4 years. I like the guys there, and they seem to be honest enough. It appears however they may have been negligent in this case. I’m astonished that this is the explanation for my transmission trouble. As “tire experts” they should have known about this issue.

Is there any other way to verify the tires as the source of the problem? Thanks… michael

It’s not much in the way of verification as far as providing definitive proof of what happened to your car…theoretically something else could have ruined your transmission, but you might want to show your mechanic this passage from an '06 Outback manual:

All four tires must be the same in terms of manufacturer, brand (tread pattern), construction, degree of wear, speed symbol, load index and size. Mixing tires of different types, sizes or degrees of wear can result in damage to the vehicle?s power train.

That’s a pretty convincing passage. Thanks a lot for the tip!

I feel obliged to discuss this with my mechanic. After all, my car is basically useless until the $3500 in repair work is done. Do you guys have any experience with mechanics ponying up after making a mistake like this? What do you think my chances are getting some kind of compensation? Or am I basically screwed? Thanks… michael

Did any of those people bother to check the fluid level before ripping it all apart?
The gear oil does not have to even be run completely out to cause noise and damage to a Subaru transaxle.

Simply being down 3 pints can do it. Being completely dry or close to it can even be catastrophic and this scenario is often caused by someone inadvertently draining the trans instead of the engine oil. The drain plugs are similar and are located close to each other. It’s not as rare as you might think so give some consideration as to whether this noise started not long after an engine oil change.

That’s an interesting point. I took the car from my mechanic to the transmission specialist who said “There was plenty of fluid, but the parts look like they’ve been running dry.” My mechanic has however performed numerous oil changes on the car. Maybe it was discreetly filled before leaving the shop? Or am I being paranoid?

I don’t think you’re being paranoid at all and I have no idea if it was discreetly filled or not.

If the transmission shop says the ring and pinion gears in the transaxle are damaged (referred to as galding when there is a lack of fluid) then that could point to a lack of gear oil.

Being low on fluid may cause damage that may not be noticeable to your hearing. When noise does occur it’s usually a humming or rumbling sound that is caused by mainshaft bearings.

When the transaxle is out or almost out of gear oil what you may notice (and this can be very distinct) is a whining sound that will vary in intensity and this is caused by the ring and pinion gears. Eventually this whining can lead to rumbling, lurching/binding, knocking, and in some severe cases a catastrophic bang. The latter means scrap metal.

Subaru transaxles are expensive; either as reman/new units or rebuilding them. I would recommend finding a used unit if possible. Proper overhaul of a Subaru transaxle really should be done with a number of Subaru-only specialized tools and the only place you will find this pile (a large pile too) of pricy tools is the Subaru dealer. Anything other than that is educated guesswork for the most part.

The most plausible explanation to me is the mismatched tires. It makes perfect sense. At this point, I’m wondering if the mechanic bears any responsibility for his negligent advice.

Are you guys pro mechanics? Do you ever compensate customers for costly mistakes you’ve made? Am I totally naive? Thanks… michael

I would probably have the car towed to either a Subaru dealer service department or a good independent shop that specializes in Subarus–or at least has more familiarity with them and AWD in general then your current guy. See what they say, and if they agree that the damage was most likely caused by the mismatched tires then you have a pretty good case for some kind of compensation. Some might say that the onus was on you as the owner of the vehicle to know about this issue with the tires, but be that as it may most small claims courts (if it came to that) would probably agree that the average person relies on those in the service industry who purport to have the requisite knowledge and ability to maintain and repair their cars precisely because they themselves do not. At any rate, your tire shop mechanic should have known that mismatched tires on an AWD vehicle were a no-no. Most reputable shops stand behind their work…but most reputable shops wouldn’t have put mismatched tires on an AWD vehicle. They would have advised you to get 4 new tires, or to get two new tires identical to the older ones and then shave them down to the same size. Your mechanic doesn’t seem to be at the top of his game, and one can only speculate as to how he’ll feel about being asked to pay for all or some of the cost of repairing your car. I would give it a shot, politely but firmly. If he laughs you out of the shop or runs you off his property, I think you have a pretty decent small claims case…if you’re so inclined to go that route.

Hey thanks Riggy. That’s good sound advice. I really appreciate it. I’m certainly not seeking a conflict. As I said, I actually like the guys at the shop. They’ve done me favors and been very helpful in the past. On the other hand, I’m out $3500 on a car that’s worth maybe $6000. (Did I mention I actually paid the car off the day before I got the diagnosis?) It’s a tough spot.

I was thinking of offering to pitch in $500 (acknowledging my partial responsibility) and asking if they would pony up the rest. If they refuse, I will reluctantly take them to court and effusively report my experience on Yelp and elsewhere.

I’ll keep everyone here posted on the outcome, if you’re interested…

I think that this is a good course of action, and I wish you much luck with the process.

In addition, I would like to suggest something else, even though it will not have any impact on the outcome of the legal process, namely that you should finally read the Owner’s Manual of your present car and you resolve that you will actually read the manual that comes with all of your future cars.

When I buy a car, I read the manual cover to cover (okay–I do skip the 20 pages on how to put on a seat belt!), and I periodically re-read certain sections if I have any question regarding the function of particular features or if I have any haziness regarding the operation of the car or its maintenance.

No matter what your mechanic should have told you, the fact remains that you could have overridden his bad advice and his lack of technical knowledge if you were simply more familiar with the car that you bought with your own hard-earned money. In the long run, we must all look out for our own best interests, and unfortunately you were your own worst enemy in this situation. Your failure to read the booklet provided by the car’s manufacturer ultimately cost you a huge sum of money.

It is for this very reason that car Owner’s Manuals are referred to as the least-read best-sellers in the world–and that is just a shame.

Once again–sincere good luck with the resolution of this problem.

Consider your advice taken to heart. Thanks to all for the help and support… michael

For what it’s worth I worked for 3 Subaru dealers over the years (none of them still around) and only mention the lack of fluid thing because it’s something I’ve seen more than several times.
The worst case I’ve seen involved a 15k miles Subaru in which a quick lube facility drained the transaxle by mistake during an engine oil change. The vehicle owner had noted a faint whine and thought they would get it looked at when they reached OK City, about 80 miles down the road. They only made it 50 miles before the trans exploded.

I’m still leaning towards the lack of fluid scenario based on the transmission shop comment about the internals looking like they’ve been running dry and IF the noise that started some months back involved a gear whine. This whine can be subtle in nature and may even be drowned out by the radio, cabin fan, road noise, etc.

A reputable shop should bite the bullet and cover any screwup. The issue here is that at this point in time none of us know what caused this problem and whether the shop should cover anything. The transmission shop who tore it apart should be able to tell you yes or no as to whether it was run low, dry, or whatever.
If the ring/pinion gears are galded and the mainshaft bearings are a little rough then I’d say there was a lack of oil.

if you go the court route beware of one thing. The shops lawyer will almost certainly point out that the tire sizing issue is clearly stated in the Owners Manual. And also in the manual is a statement of something like, It is the owners responsibility to read and understand this manual before operating this vehicle. Just a word of caution.