A friends Legacy sedan broke a rear brake rotor a few weeks ago.  I 4" section of the rotor broke off and jammed up the drive line.  He had the brakes replaced and it drove fine for a few weeks.  Yesterday he got the P0700 code.  He cleared it and it has not come back.  I suggested a full inspection of the driveline to make sure it's OK.  Brake rotor breaking is very strange.

Did that cause the Transmission Control CEL?

Probably unrelated. May need a valve body soon though. Those early top-loaders have issues with TC lockup solenoids. 

GD

5 hours ago, lmdew said:

A friends Legacy sedan broke a rear brake rotor a few weeks ago.  I 4" section of the rotor broke off and jammed up the drive line.

Do you know if the rotors were ever replaced or are not OEM, or if it was ever in an accident?

Any chance the rotor shards damaged the ABS sensor or wiring?

Was the car moved, towed or repaired in any odd way when the rotor broke?

Id guess mechanical failure alone would not compromise the transmission in that way but I have no solid reason to guess that.

 

Thanks.  Napa brake parts.  Not sure on the history.

Looked fine underneath.  Passenger side Brake backing plate is torn across the bottom.  Still trying to figure out how something shot up in there going down the freeway.  Tire and rim are fine.  ABS no visible damage.

GD can the TC lockup solenoids be tested?  Can I do it or does it need to be a good transmission shop?

Thanks,

Larry

16 hours ago, lmdew said:

Thanks.  Napa brake parts. 

Hmm - makes me wonder if aftermarket rotors are weaker. 

Numbchux recently posted some similar CVT diagnosis/repair info:

 

Interesting.  Thanks

Generally it will throw a manufacturer specific code on the generic OBD-II, but the presence of the 700 code is a clue also - that indicates that the TCM sent a MIL request message to the ECM. So there should be additional information available from the TCM such as TCM specific codes or freeze-frame data. More advanced scanner would be required to communicate with it directly. 

GD

Thanks.  I recommended Jim at Cascade Subaru.  Great one man shop in Cascade CO.

Code came back.  $1500 from a Trans shop!  Ouch.

He has it into a good Trans Shop.  GD if it's just the TC lockup solenoid can you change just it instead of the complete valve body?

Thanks, Larry

4 hours ago, lmdew said:

He has it into a good Trans Shop.  GD if it's just the TC lockup solenoid can you change just it instead of the complete valve body?

Thanks, Larry

According to Subaru, no. There are internet sources for the solenoid - even Amazon. But there aren't any trustworthy vendors that I've found and the reviews are pretty mixed. Many people report repeat failures within days, weeks, or months with aftermarket solenoids. The sure bet is to get a valve body from Subaru. All of them have TC solenoid failures. My local dealer keeps 7 of those valve bodies in stock right now due to very high demand.

It is a very easy job though. Those are top loaders. You pull the intake and throttle body and the valve body drops right into the top of the trans. Anyone that knows which end of a wrench to hold can do it. It certainly doesn't need a "trans shop" - whatever that means...... incidentally I really don't see much use for that level of specialization. I've repaired more Subaru transmissions than most "Transmission Shops". Better to have a someone that's brand familiar than a generic shop that claims to handle all transmissions. IMO. Most "trans shops" in my experience are not trustworthy. They prey upon the fact that automatic transmissions are basically Magic to 99% of the population and they know that if you're in their house you already basically suspect the trans is the problem if not completely toast...... it's real easy to scam people in that situation because chances are they have no idea nor do they even know anyone that has a basic clue about the JFM that takes place between the engine and the prop shaft. 

Back in the day when you needed a hydraulic schematic and someone that has experienced about 25 years of trial and error jamming micro-drill-bit holes into Turbo 350's, 400's, 700R's, and 'glide's - it was a thing. There's a (very) few guys like that still around - most are building 400's and 'glide's for the drag and street outlaws scene's. Anymore though that level of knowledge is not required as everything made since the 90's is computer controlled and only needs a good understanding of the fundamentals of operation and a keen eye for proper assembly. 

GD

Edited July 25, 20214 yr by GeneralDisorder

Thanks GD.  Always lots of good information.

Edited July 26, 20214 yr by lmdew

Transmission shop pulled P2760 they said indicated 2nd pulley sensor.  Of course it was driving fine while there.  More research I think.

 

Good info.  I tried to upload the file but it was to large.  Here's the link:

https://atracom.blob.core.windows.net/webinars/import/subaru_lineartronic_cvt_introduction.pdf

He went to the You Pull and got the 2nd pulley sensor and installed it.  So far so good.  Nice!

23 hours ago, lmdew said:

He went to the You Pull and got the 2nd pulley sensor and installed it.  So far so good.  Nice!

Thanks for that pdf, excellent resource.  He was able to replace it without much trouble?

The Sensor was easy, he had no problem.