Gen 2 LV Transmission Fluid

[bradsm87]

Originally Posted by DrinkenBRZ

Have they not revised tolerances elsewhere? Thinner may be more appropriate if so.

If the transmission was re-engineered for thinner fluid, the first thing they would do is change all the synchros, which they haven't.

Ball or roller bearings used in manual transmissions don't run different tolerances to suit different oil viscosity to my knowledge.

People have reported draining the stock LV fluid after a couple of autocross events and it comes out grey and watery. Changing to something thicker fixes the issue. I'm not taking a chance on it with a brand new car. I don't care about the 0.1% better fuel economy. I want the extra protection.

[JohnH]

Id back that statement up. The manufacturers are all about their corporate average fuel economy, so if they can convince those in power that thinner trans oil will net them lower fuel usesage, they will do it as long as most transmissions last the warranty period.

I don't use 0w20 or 0w16. I run 5w30 synthetic in my engine for the same reason.

[sato]

I thought the use of the thinner fluid was to deal with shifting issues when cold (not really fuel economy). If we beat car hard (track, autocross, etc.) then maybe 75W90 might provide better protection (for higher heat scenarios).

Guessing... then again, not all 75W90's are the same, and I hated my factory fill. Valvoline 75w90 refresh was even worse. The other 75w90's I tried were ok, but slightly thinner has given me better results (oil mix).

Hopefully, some other soul tests such mixes/brands to ease our minds.

[DrinkenBRZ]

Originally Posted by sato

I thought the use of the thinner fluid was to deal with shifting issues when cold (not really fuel economy). If we beat car hard (track, autocross, etc.) then maybe 75W90 might provide better protection (for higher heat scenarios).

Guessing... then again, not all 75W90's are the same, and I hated my factory fill. Valvoline 75w90 refresh was even worse. The other 75w90's I tried were ok, but slightly thinner has given me better results (oil mix).

Hopefully, some other soul tests such mixes/brands to ease our minds.

The LV fluid is actually thick by todays standards at around 9cst @ 100degC. Similar to Pennzoil Synchromesh, which Rice Classic and maybe some others have had good luck with including on track. I may try it in my 2020 here soon, but my twin is my daily for now.

FWIW Valvoline doesn’t make a 75w90 additized for synchronized manual transmissions, so not surprised it shifted poorly. This has nothing to do with GL5 mind you as most, if not all, GL5 gear oils are yellow metal safe now and have been for over a decade.

[bradsm87]

Originally Posted by DrinkenBRZ

The LV fluid is actually thick by todays standards at around 9cst @ 100degC.

Where is this published? I don't believe Toyota publish it.

Redline MT-LV, which is their Toyota LV formulation, is 6.5 CSt @ 100C.

[bradsm87]

Originally Posted by sato

I thought the use of the thinner fluid was to deal with shifting issues when cold (not really fuel economy). If we beat car hard (track, autocross, etc.) then maybe 75W90 might provide better protection (for higher heat scenarios).

Guessing... then again, not all 75W90's are the same, and I hated my factory fill. Valvoline 75w90 refresh was even worse. The other 75w90's I tried were ok, but slightly thinner has given me better results (oil mix).

Hopefully, some other soul tests such mixes/brands to ease our minds.

Yep in part it would be to improve shifting (at the expense of transmission lifetime)

I'm not saying go out and put 75w-90 in but I think Redline MTL 75w-80 and MT-85 75w-85 would both be great options.

[DrinkenBRZ]

Originally Posted by bradsm87

Where is this published? I don't believe Toyota publish it.

Redline MT-LV, which is their Toyota LV formulation, is 6.5 CSt @ 100C.

There’s a voa on the WRX/STI site, which agrees with the SDS at the dealer.

https://forums.nasioc.com/forums/sho....php?t=2933689

[bradsm87]

Originally Posted by DrinkenBRZ

There’s a voa on the WRX/STI site, which agrees with the SDS at the dealer.

https://forums.nasioc.com/forums/sho....php?t=2933689

Subaru Extra MT in that link is a 75w-80, similar to Redline MTL. Toyota LV 75W is thinner than that. My understanding is that Toyota LV 75W is used in all 2022+ GR86/BRZ.

[DrinkenBRZ]

Originally Posted by bradsm87

Subaru Extra MT in that link is a 75w-80, similar to Redline MTL. Toyota LV 75W is thinner than that. My understanding is that Toyota LV 75W is used in all 2022+ GR86/BRZ.

Mostly correct. Subaru dealers here will install their 75w80 during a service. From the factory won’t know until we, at least, get a uoa from a 2022+. But, I’d wager they are all getting Subarus from the factory since they control production and the transmission is Subaru. All else I agree with and would support Redline MTL. I would not run anything below 9CST in these given the lack of evidence of a major redesign of the unit. 75w90 make sense for track use.

[bradsm87]

Originally Posted by DrinkenBRZ

Mostly correct. Subaru dealers here will install their 75w80 during a service. From the factory won’t know until we, at least, get a uoa from a 2022+. But, I’d wager they are all getting Subarus from the factory since they control production and the transmission is Subaru. All else I agree with and would support Redline MTL. I would not run anything below 9CST in these given the lack of evidence of a major redesign of the unit. 75w90 make sense for track use.

It's an Aisin transmission and it's not used in any other Subarus in that form. The trans is much more similar to the one used in the Lexus IS200 and other low torque RWD vehicles from various manufacturers.

See attached image straight from the Subaru BRZ Owner's manual. The fluid you referred to that's factory fill in some other Subaru models that is 9CSt at 100C is not used in the BRZ. The BRZ Uses Toyota LV 75W which is thinner.

[DrinkenBRZ]

Originally Posted by bradsm87

It's an Aisin transmission and it's not used in any other Subarus in that form. The trans is much more similar to the one used in the Lexus IS200 and other low torque RWD vehicles from various manufacturers.

See attached image straight from the Subaru BRZ Owner's manual. The fluid you referred to that's factory fill in some other Subaru models that is 9CSt at 100C is not used in the BRZ. The BRZ Uses Toyota LV 75W which is thinner.

No dealer within 100 miles of here is. Parts counter guy showed me Monday Subaru NA is spec’g the referenced fluid for service fills. Put up a uoa of a fresh 2022 or 2023 or shut up. I’m happy to be wrong at that point and we can exchange egos.

[bradsm87]

Originally Posted by DrinkenBRZ

No dealer within 100 miles of here is. Parts counter guy showed me Monday Subaru NA is spec’g the referenced fluid for service fills. Put up a uoa of a fresh 2022 or 2023 or shut up. I’m happy to be wrong at that point and we can exchange egos.

I’m not talking about which fluid dealers are using when servicing. I’m talking about the factory fill fluid and the fluid the manual is referring to.

You said LV fluid is 9CSt at 100C. It isn’t. That’s a different fluid. Some (or even many) dealers may well use Subaru 75w-80 fluid for servicing but that is not the LV fluid.

[Pat]

Good discussion, people. I'm looking forward to learning more about this. I have a bunch of fluid for my now-defunct first generation BRZ and wonder if I should be using it when my second generation car shows up in a few months.