Two transmission issues
 

Howdy yinz all -


2013 FR-S with 52,000 miles. Solo Spec Coupe. I have replaced the gear oil with Mobil 1 about 10,000 miles ago. Car is used for a one or two HPDE/TT events a month 8 months of the year, and some autocross.


First, my transmission has developed a little whine when engine braking. Sometimes it's louder than other times, no change in performance. As a replacement transmission is running about $500 used, I am inclined to run it until it breaks and then just replace it. However, if this is a known problem and it would take only replacing a bearing that is easy to reach after the transmission is out of the car, I'd consider doing that. Anyone had a similar experience?


Second, only when on track and when turning to the right exiting a turn, I have difficulty finding third gear sometimes. Is this a common issue and is there a fix?


Thank you in advance.

Unless things have changed I don't think Mobile 1 makes tranny fluid to our specs.
The only gear oil they make is for the diff.
Unless you put the stuff for the diff in the tranny?

Not sure on the transmission whine problem, but I've experienced the same issue you mention as your second concern.

Simple answer is to install a transmission brace mount (many companies make them - I installed the Perrin one) as well as the shifter bushing upgrade (same thing as before - I installed the Perrin one again).

Both of these inexpensive pieces seemed to have fixed that concern/issue.

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Sorry - It was Mobil 1 in the diff. Motul 300 in the transmission at 46,000 miles. Thank you.

Because it is SSC, I can't put a transmission brace mount or bushing upgrades in. However, maybe it is time to explore new OE bushings. Thank you

Well I'm not a fan of Motul, so naturally I would say it's due to the shitty tranny fluid. Lol

Have you tried changing tranny fluid?
As a Redline fan boy I would recommend Redline. Cause it's far superior to any Motul piss water.

I haven't tried changing it again.

+1 Redline MT90 but it probably won't do anything for the whine.

I with the peanut gallery here as I don't believe Motul 300 belongs in the tranny - it's a gear lube and belongs in the diff, assuming you're talking about 300v 75w-90. I've had crunchy synchros with MT90 along with Amsoil Synchromesh in a race track environment. I have great experience racing on Penn Synchromesh. I think the redline MT-LV may work too.


As for the whine - that's likely a bearing on either input or output shafts. That should be an easier and MUCH less expensive fix vs putting in another used tranny. I would also put in new synchros while you're in there. It should only take an afternoon to pull the tranny and refresh it.

Gear 300 is literally listed as a transmission fluid by Motul...

https://www.motul.com/nl/en/products/gear-300-75w90


300v is an engine oil.

Including the 'v' was typo.

I smell what you're stepping in - and Motul isn't the only company to market gear oil as a manual transmission fluid, but just because it's marketed as such, doesn't make it so. A full syn "Gear oil" that's a GL4+GL5 really doesn't belong in these transmissions. We can agree to disagree and leave it at that. Motul, just like Torco/Redline/Amsoil are fine companies but not all their products are ideally applicable to the thing they claim they are ideally applicable to.

I haven't shopped here in the past but looks like a good source to buy new transmission bearings and synchros.

https://estore.subarupartswarehouse....nsmission.html

Hold up. GL4, GL5 are ratings that require products to meet a certain specification. The specification for our transmissions are chosen by the manufacturer.

Are you saying Subaru doesn't know which GL spec to list for the transmission or lubrication companies are lying about meeting the spec? I don't care what kind of oil someone calls something, it either meets the spec or it doesn't.

I can definitely claim that Subaru/Toyota spec GL-3 - it's in your manual.

You know what doesn't meet spec?...marketing. :D These specs are a range. There can be quite a difference in their formulation, additives and viscosity even though they all say GL4 on their label.

While a GL4 can replace a GL3, a GL5 is different as it's designed specifically for hypoid gears (much more EP additives) and its chemical comp is often destructive to brass metals (like synchros). Transmissions like ours like thin fluid - the gears are all moving in the same direction and the synchronizers rely on friction to do their job. Differentials are hypoid gears need loads of EP additives and sheer enhancers to keep the faces of the opposed gears from destroying each other. These are very different needs and with all the choices out there - I cannot recommend a fluid that claims to be good at both and is frankly too thick (50% thicker than OEM fluid) and too slippery for our synchros in this specific operating environment.

Gear 300 marketing literally says: "Unshearable oil film in extreme conditions". Sounds great in my differential (and it is in my diff) but not for my synchros.

Don't get creative with transmission oil. I say this as someone who has lost a few transmissions from the use of synthetic trans oil (other applications). Use whatever GL-3 Toyota or Subaru has available or Penzoil Synchromesh which states that it is suitable for applications specifying GL-3.