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.

You're assuming the invoice wasn't lazily copy-pasted from another invoice.

I've known enough service writers to know that half of them couldn't tell you the difference between gear oil and engine oil without the sticker on the bottle. another healthy dose couldn't tell you what gear oil even is, but the tech said you needed it, and it had a book time listing in the quote system.

Try being a little more deliberate with your shifts. After 3 years of driving the car I went to an IRP short shifter and started having the same issues shifting at high RPM. Just holding the clutch pedal down a fraction of a second longer before making the shift and it went away.

Putting this video in about gear oils from a transmission expert. Skip to 11 minutes in to get the relevant material

https://m.youtube.com/watch?v=Z7NpsMZ9pBQ

Maybe somebody will find this information useful

I don't know specifically about our cars, but I am a liscenced tech and if a car doesn't specify the use of GL5 and you put GL5 in it, you will ruin the soft metals/yellow metals. Those are what your synchro rings are made of. The additives in GL5 attack yellow metals over time, causing premature wear. Worn synchros give you the symptoms you are speaking of.

I also know that there are some modern GL5 rated oils that are made NOT to damage yellow metals, so you could use those.

I'm super conflicted since knowledge points to don't use GL5 but Subaru's OEM fluid is GL5. 2017 Brz manual does specify GL3/4/5 though but if our syncros are brass I wonder why.

Do you know how extreme the pre-mature wear is using GL5?

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That's exactly what I don't understand... In the 13-16 owners manual it just says GL-3 or higher grade (something to that extent). But then in 17+ it says GL 3/4/5. But the transmissions are identical from what I can find. So they literally recommend using oil that could cause serious damage to the transmission. This is kind of why I don't think I will pursue this with them. They will probably just point to that and say GL-5 is fine to use.

It's your clutch throw-out bearing (TOB) gone bad. They get fried every 55,000 miles or whatever. Get the revised updated part installed and your shifts should be crisp again. Also recommend installing the whiteline / perrin positive shift kit.

Also change your transmission fluid and differential fluid whenever you feel like! I change mine every 35,000 miles! I use motul gear 300. My car is at 135,000 miles if you want a reference.

didn't read any other posts in this thread lol.

For whatever it is worth.... I haven't read previous posts, so if someone already mentioned this... oh well!
GL3 & GL4 oils do not have as much additives as an GL5. The theory is that the additives build up a protective sacrificial layer on ferrous materials to prevent wear & tear. The more pressure and temperature, the better the ZDDP film build up. However, this protective layer can be harder than the yellow metals. So in an event of extreme shock, the protective layer will take away the yellow metals with it and cause pitting. That's why GL5 is not recommended for synchro transmissions.

BUT... I emailed Subaru customer service, and they said that as long as it's Subaru transmission oil, it should be fine. I don't expect much expertise from a customer service guy, so I didn't nag him too him.

Anyway, back to your car....

You picked a car that has almost 60k miles. Who knows what the previous owner did/didn't with maintenance. If the dealership put GL5 recently, it won't be long enough for it to be the cause. It is most likely the previous owner.
And yes, it does sound like a synchro issue. That does not mean that the synchro tips are rounded off or blunt, it could also mean it's not getting enough friction. If there is no physical damage, then a simple oil change will fix it. But if there is (not to sound negative), hopefully the dealership might help you out since you just bought I from them.

@SockMonkey @chipmunk
I've been using Motul Gear 300 GL-5 in the transmission and diff for over 100,000 miles (changed regularly) and never had an issue with it. If I ever had a problem with shifting, it was because the throw out bearing burning itself up, or the transmission mount having too much flex and lash when shifting (fixed with whiteline part).


Its your throw out bearing. At your mileage its very common for the factory throw out bearing to go out, cause crunching shifts. Get the new revised throw out bearing and your shifts will be crisp again.

Yea but he's saying it only happens at 3rd-4th gear shift.

Exactly, 3rd to 4th. I can quickly shift 1-2 2-3 at high rpm with not much trouble, but that 3-4 always crunches if i try too quickly over say 4.5-5k rpm. And if you google that specifically, 3rd to 4th crunch, (which i did over the last few days) you'll find many threads from 2013-2014 with people complaining about the same issue. But subaru simply replaced their transmissions under warranty. So now it makes be wonder if maybe this is just a defect from the beginning and the original owner never noticed.

I'm pretty confident maintenance and what not was done well by the previous 2 owners, even had decent paperwork (such as the invoice I mentioned from last year).

And I thought Motul was GL-4 and 5. Like its doesn't have the additives typical GL-5's have, but it still met the requirements.

Anyway, as of right now, im going to just change the oil with some good GL-4, and probably not pursue Subaru. If it becomes an bigger problem or doesn't go away with new oil, I'll just swap the tranny when I do the clutch. I'm leaning towards Amsoil MTG but I've read good things about Redline's MT-90. I can get the Amsoil locally too, haven't found MT-90 yet though.

I'm also planning on doing a transmission swap. I ordered a set of the carbon fiber/brass synchro rings from Synchrotech and will be replacing the synchros in a spare transmission I ordered off eBay. I also use the Amsoil in my transmission and honestly, especially in the cold climates of Northern Alberta, the auto parts store Redline fluid was much better suited for my uses. The redline was more solid down low and didn't grind, but up high it often grinded. The Amsoil fluid grinds down low but is flawless up high in the tach. But I won't be using an Amsoil fluid again in there. Not suitable enough for my uses

I'm thinking that whoever owned my car before me blew up the transmission in this car. I've only owned it for around 7k miles and I already feel like the synchro rings are worn out. Hoping the aftermarket synchros will help me

Did you ever find out what it was? I have a used 2015 and it's the same. 3-4 crunch only when fast shifting or high rpm close to redline.

Adjust your clutch engagement point. A half-turn fixed all my clutch / clearance issues after I sorted the drivetrain flex with the positive shift and positive traction kits.