3rd to 4th crunch on '13 BRZ, dealer used GL-5 transmission fluid, are they liable?
 

So I picked up a '13 BRZ with 59k miles a few weeks ago, obviously outside the 5yr/60k drivetrain warranty. After getting use to the car I started to notice a crunch/grind when I was shifting 3rd to 4th at higher rpm, like a highway on ramp. After some googling I found this was/is a some what common problem, usually fixed be replacing the tranny. I figured it needed a fluid change, but remembered the previous owner saying they has it serviced. I got him to send me the invoice and it says 3 quarts of "SOA427V1700 HIGH PERF GEAR OIL 75W-90". When I google that, I find that it is Subaru's oem oil and it is a GL-5 gear oil. Everything I read says these transmissions should only ever have GL-3/4. This was done at 51k.

I was originally planning to change the fluid for some redline MT-85 or 90. But before I do that, would I have any grounds to pursue repair/replacement from Subaru? Could having that gear oil in there for 8k miles have caused this crunch I'm experiencing from damaging synchros?

Definitely bring it to their attention. They dun goofed

Talked to a service representative today and explained my issue and what the invoice showed. I don't think he quite understood because he kept saying "it doesn't sound like a fluid issue, it sounds like a synchro issue" and I said, yes caused by the fluid installed from the dealer...

Scheduled an appointment for the 27th. We'll see.

I doubt it, the oil weight is still 75W-90.

I would suggest you replace the clutch fluid and bleed the clutch fluid system to see if that helps. Even if not, it wouldn't hurt to replace that fluid anyway.

The OEM fluid in these cars sucks and causes poor shifting, especially when cold. Most of us swap out for Motul, Redline, or Amsoil.

A quick search of shifting issues would have shown you this. No need to make two threads about it.

I don't think the clutch fluid is going to cause grinding in 4th at high rpm. The clutch disengages fine, no dragging, im depressing the pedal all the way. Everything else is fine. Besides, brake and clutch fluid was replaced at the same time.

Everything I've read says the sulfur and phosphorus additives put in to meet the extreme pressure rating of GL-5 corrode yellow metals, like copper and bronze, over time. Which is why they are bad for transmissions with bronze synchros. Its seems to be quite common knowledge if you just search like "GL-5 instead of GL-3".

This isn't oem fluid though, they shipped originally with a GL-3 fluid. Then Subaru put their current OEM Extra-S GL-5 fluid in. Which is known to be bad for our type of synchros.. Did you even read my post?

And I made two posts because this branches both topics. One of oil questions, one of warranty/liability.

And if you go to your other thread, someone posted the newer manual which says GL4 and GL5 are acceptable. Either way the OEM fluids sucks new and old.

Probably not worth the headache anyway.. I should probably just swap the fluid and call it good. Save for a replacement down the line..

Some guys use Motul Gear 300 which is GL4/5. I like Redline MT-90 since I can get it at most auto parts stores and is GL4. Took care of my syncro crunchiness.

I doubt you'll have an easy time pursuing this. Might just be way easier to find a decent condition used transmission and swap it in.

Kind of puts me back to square one. After looking at all the options, I had originally come down to 2 options. Redline MT-90 and Amsoil MTG, read great reviews about both.. I have a friend/tuner who it a Amsoil dealer and he has their MTG in stock. I can only fine MT-85 locally. So i either order MT-90, or pick up some Amsoil.

Is it consistently crunchy? I get the occasional crunch here and there and it's "one of those things" that happens with these cars.

Its just like I said. If I am driving around normally it doesn't happen. But if I try to shift at high RPM, like when accelerating on an on ramp it crunches. The higher the rpm the more noticeable the crunch.