[Shiny]

Thanks again chevymad. A TSB is not folklore!

Sirrotica - I agree 1/4" difference in circumference should be inconsequential. Why the TSB was issued is a good question. Would be an interesting engineering back-story. I have a hard time believing they could avoid a warranty claim based on this in a courtroom but like you suggest, it may have been a tactic to compensate for a bad design and cut their losses.

We have a 2013 Outback that we bought in large part because it was old tech and all the bugs were worked out. Then it started burning oil and we got a notice saying they screwed up (I think they changed rings to improve emissions or mileage) and would warrant against excessive oil consumption. Ours burned about a quart every 5000 miles after owning it a year. When we tried to get it fixed, they had decided the bar was something like a quart every 1000 miles. Pretty sleazy IMO but ours hasn't gotten worse since.

We got a similar notice on the CVT for the same car... again we were surprised by a very mature design causing trouble. Bad engineering? Yes, I would say so... but having worked as a reliability engineer for 20 years (not automotive) I understand the business pressures that lead to these situations.

[mgarblik]

Subaru is one vehicle brand my school experience and my shop experience is very limited in. They are not very popular around here and my school doesn't have any real industry connection with the brand. The largest dealer in our area is a dealership that operates out of a house looking building with a little attached pole barn. That being said Subaru sells only 4wd/awd vehicles, and their tolerance may be very small for tire diameter, I just don't know. The TSB seems to indicate that. Tire stores find themselves in the middle of this mess. They are in the business of selling tires so it's in their best interest to use the tightest tolerance they can find, (Subaru), and transfer that to all makes and models with AWD. Only have to remember one line of information and you sell lots of extra tires. Not saying it's right, but I understand the thinking. They are making an error on the safe side, but separating some customers from their money when not necessary.

[Sirrotica]

Originally Posted by chevymad

Screen capture of the TSB

I never doubted there was a TSB, I doubted the engineering from subaru. Keeping your tread depth within .040 from to rear in a daily driver is complete madness.

Reading from what a subaru service tech for 12 years, says about repairing them, a valve body solenoid failure within the subaru transfer case takes out the viscous clutches normally. He mentions nothing about having to keep tires within.040 tread depth as a cause of the failures. Subaru has a crutch to fall back on to explain the failures to the customer, transferring the cost of repair to them, rather than fixing, and warranting their engineering flaw.

Further research says in Canada, subaru does not have a mandatory tire pressure monitoring system (TPMS) mandatory and the transfer case can be damaged without constantly monitoring tire pressure as is required within the US.

Which version do you take more stock in, the experienced subaru service tech that says the valve body solenoid fails, causing viscous clutch failure, or the TSB that blames tire pressure, and wear for the failure? It's pretty easy for the dealership to walk around the car and see a tire low for pressure, or a tire worn .040 more than the rest. "Here's the problem car owner, you neglected your tires, and we have a TSB here to refer too".

You lock out the rear drive system, as has already been mentioned, and presto, no symptoms because the differential is no longer in play with half the system locked out. You proved the differential is damage beyond a shadow of a doubt, and you pointed out a tire flaw which caused it. Standard operating procedure is replacing the damaged differential, along with the valve body solenoid, and any other parts that are damaged upon tear down. A wiring harness was also noted to have failed to the tune of $650.

Then correcting the tire flaw that may, or may not, have had anything to do with the differential failure. Customer pays and drives off until the valve body solenoid, or some other part fails again. If it were me, I'd be selling off this engineering marvel before it costs me another $1000 to $2000 repair. Actually I research most every major purchase, before I make it, so I would never have purchased it to begin with.

Head gasket failure, causing ultimate engine failure is a common problem among subaru owners. I suppose they also seek to lay this on the owner, rather than remedy the ultimate problem.

Google AWD transfer case failure, subaru and Jeep are the main subjects that appear. The Jeep system seems to have a better tolerance for tire flaws and variations, and air pressure variations than subaru does.

No AWD vehicle will be sitting in my driveway, I've never had faith in them since the 70s when GM, Jeep, and dodge first tried them in trucks. At that time Dodge was the worst followed by Jeep and GM. GM had a conventional center differential that had no limited slip that lasted the longest.

Problem back then was the chains stretched and commonly wore a hole in the exterior of the transfer case. The front axles had conventional U joints being driven 100% of the time and failed with regularity. CV axles were an improvement, but US manufactures went back to conventional part time four wheel drive to reduce repairs, and also boost fuel mileage. Gas shortage kind of killed off the AWD trucks and SUVs in that time frame.

The aftermarket had kits to convert the AWD systems to part time, they sold a ton of them too. It made your truck or SUV a much better vehicle, less wear on the front axle and attendant parts, and improved fuel mileage 15-20%

[mgarblik]

Originally Posted by Shiny

Thanks again chevymad. A TSB is not folklore!

Sirrotica - I agree 1/4" difference in circumference should be inconsequential. Why the TSB was issued is a good question. Would be an interesting engineering back-story. I have a hard time believing they could avoid a warranty claim based on this in a courtroom but like you suggest, it may have been a tactic to compensate for a bad design and cut their losses.

We have a 2013 Outback that we bought in large part because it was old tech and all the bugs were worked out. Then it started burning oil and we got a notice saying they screwed up (I think they changed rings to improve emissions or mileage) and would warrant against excessive oil consumption. Ours burned about a quart every 5000 miles after owning it a year. When we tried to get it fixed, they had decided the bar was something like a quart every 1000 miles. Pretty sleazy IMO but ours hasn't gotten worse since.

We got a similar notice on the CVT for the same car... again we were surprised by a very mature design causing trouble. Bad engineering? Yes, I would say so... but having worked as a reliability engineer for 20 years (not automotive) I understand the business pressures that lead to these situations.

Oil consumption of 1 quart per 5000 miles is considered excellent and no issue at all. Even as conservative as I am, I would consider 1 quart per 5000 miles just fine. IMO, as an engine approaches 1 quart every 2000 miles, you have a problem in it's early stages. At a quart per 1000 miles, manufacturers begin to offer repairs. My daughters Honda CRV has been using 1 quart every 1750-2000 miles. Honda offered to replace the piston rings no charge. It was 6 years old. They do the replacement with the engine in the chassis. I considered it, but with the possibility of all the other things that can get screwed up doing major surgery on a vehicle 6 years old with almost 90K miles on it, I advised her to just add oil when needed. Less headaches that way and everything else works as it should.

[chevymad]

I live in the PNW and subaru's are literally everywhere. I almost believe they're the most popular brand of car. After working on them however, I won't own one. I've seen a couple CVT's go out and almost all of them start burning oil and catalytic convertors by 150k. Plus the head gasket issues. When someone comes in and wants their codes read, I can almost tell them immediately there will be a p0420 code.

[Shiny]

Mike - We have shifted topics but thanks for the reassurance on the oil consumption. Car has ~70K miles, runs fine, and has been very reliable... more-so than any other car we have ever owned. The oil consumption is a nuisance by comparison to issues we've had with other cars.

chevymad - LOL we bought our Outback while living in Seattle area and I agree I have never seen so many Subies anywhere, although they are also pervasive in CO. As to long term durability, we figure the extended warranty will cover us on the rings and CVT until we get sick of it and trade it in.

Sirrotica - I'm going you have you research the next vehicle I consider buying!

[Sirrotica]

Originally Posted by Shiny

Mike - We have shifted topics but thanks for the reassurance on the oil consumption. Car has ~70K miles, runs fine, and has been very reliable... more-so than any other car we have ever owned. The oil consumption is a nuisance by comparison to issues we've had with other cars.

chevymad - LOL we bought our Outback while living in Seattle area and I agree I have never seen so many Subies anywhere, although they are also pervasive in CO. As to long term durability, we figure the extended warranty will cover us on the rings and CVT until we get sick of it and trade it in.

Sirrotica - I'm going you have you research the next vehicle I consider buying!

Fine by me, having worked on other peoples cars most of my adult life, I hate to fix my own. That's the reason I've driven Pontiacs, and still do, I hate fixing my daily drivers. I also seldom buy new cars (2 in my lifetime) and when I retire them they are worn out, and I got everything out of them that I could. BTW, I'll never buy another new GM car after GM killed Pontiac off, I'm still bitter about it 11 years later........................

It's also the reason my cars and trucks have by pass oil filters on them, it safely extends oil changes because the oil never gets dirtier than when you poured it in the crankcase, and it's still clean years later when you finally drain it. Saves a ton of money especially in daily drivers and extends the life of all the pressure oiled wear items in the engine by 7 fold.

My trucks are all powered by diesels, the shove-or-leave-it's (chevrolets, in case you don't know that terminology) have the 6.5 Detroit turbo diesels in them because I don't like SBC, or BBC engines, and the IH wrecker has the ever dependable IDI 7.3 IH V8 diesel.

When you work on cars daily you get to know what has better engineering, as Chevymad has said, he'd never buy a subaru because he sees the results of poor engineering on the job.