Trans & Diff Fluid Change at 10,000mi? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

formulaBRZ · 01-11-2023, 01:26 PM

Hey all,

I'm considering picking up some Red Line MT-90 and 75W85 gear oil and having a reputable independent shop perform a trans and diff fluid change at 10k miles.

My idea here is similar to the philosophy of doing an engine oil change after the 1000mi break-in to flush any undesirable metals - However, I'd be doing the trans/diff after about a year of ownership.

It seems the general consensus is that factory fluids suck, but would swapping to Red Line and flushing the factory gear oil provide any benefit this early in the life of the car?

OkieSnuffBox · 01-11-2023, 01:45 PM

Yes. I probably would have done it sooner.

I'm about to have the 1k mile oil change done on my '23. I plan on doing the trans/diff sometime between 1k-2k miles.

formulaBRZ · 01-11-2023, 01:52 PM

Quote:

Originally Posted by OkieSnuffBox

I'm about to have the 1k mile oil change done on my '23. I plan on doing the trans/diff sometime between 1k-2k miles.

I did the same, and then again at 5000mi (dealer offered a 2x/year oil change program for dirt cheap so figured why not before the year ended).

Thanks for the feedback, glad I'm not the only one thinking about doing an early fluid change on the trans/diff. Longevity is the goal with this car for me so not opposed to some early TLC on the drivetrain.

otter · 01-11-2023, 04:12 PM

Just note that the 2nd gen doesn't have the same trans fluid recommendations as the previous gen. It calls for LV - I put the Redline LV fluid in my trans at 5k miles. Haven't bothered with the diff yet (I'm at 9k).

dragoontwo · 01-11-2023, 04:15 PM

Quote:

Originally Posted by otter

Just note that the 2nd gen doesn't have the same trans fluid recommendations as the previous gen. It calls for LV - I put the Redline LV fluid in my trans at 5k miles.

This is true. I suspect that they made the move not for performance, but to try to eek out a bit more fuel mileage.

I have the RedLine MT-LV in mine now and have had no issues so far.

formulaBRZ · 01-11-2023, 04:34 PM

Quote:

Originally Posted by otter

Just note that the 2nd gen doesn't have the same trans fluid recommendations as the previous gen. It calls for LV - I put the Redline LV fluid in my trans at 5k miles.

Thanks! Someone on another thread mentioned that this had changed as well. I think dragoontwo is exactly right that this change is for FE reasons. Interestingly, Red Line still recommends MT-90 for the 2nd Gen on their website. Probably just a carryover suggestion from the 1st Gen.

Since my BRZ is only on daily-driving duty for now it seems like sticking with the recommended LV oil might make the most sense.

dragoontwo · 01-11-2023, 04:40 PM

Quote:

Originally Posted by formulaBRZ

Thanks! Someone on another thread mentioned that this had changed as well. I think dragoontwo is exactly right that this change is for FE reasons. Interestingly, Red Line still recommends MT-90 for the 2nd Gen on their website. Probably just a carryover suggestion from the 1st Gen.

Since my BRZ is only on daily-driving duty for now it seems like sticking with the recommended LV oil might make the most sense.

Don't worry too much about it.

formulaBRZ · 01-11-2023, 05:00 PM

Much appreciated!

On an anecdotal level, are you satisfied with the MT-LV as an improvement over stock fluid? Noticeable difference? Main area I'm looking for improvement in shift feel is during those low temp shifts - maybe the first 5-10 minutes of driving where I'm still babying everything.

OkieSnuffBox · 01-11-2023, 05:55 PM

Quote:

Originally Posted by formulaBRZ

Much appreciated!

On an anecdotal level, are you satisfied with the MT-LV as an improvement over stock fluid? Noticeable difference? Main area I'm looking for improvement in shift feel is during those low temp shifts - maybe the first 5-10 minutes of driving where I'm still babying everything.

For what it's worth. EVERY car I've ever put fancy synthetic fluid in the transmission has made them shift even worse when cold.

E30s, 350Z, MazdaSpeed 3, Mustang GT, 1st gen BRZ. But once warm, the shift quality is markedly improved over stock fluids.

dragoontwo · 01-11-2023, 06:03 PM

Quote:

Originally Posted by formulaBRZ

Much appreciated!

On an anecdotal level, are you satisfied with the MT-LV as an improvement over stock fluid? Noticeable difference? Main area I'm looking for improvement in shift feel is during those low temp shifts - maybe the first 5-10 minutes of driving where I'm still babying everything.

For me, is day the MT-LV is about the same as stock.

ruturaj001 · 07-10-2023, 06:10 PM

Quote:

Originally Posted by dragoontwo

Don't worry too much about it.

I am curious what was the source (name of file) of this?

dragoontwo · 07-11-2023, 06:27 AM

Quote:

Originally Posted by ruturaj001

I am curious what was the source (name of file) of this?

The lower link in my signature.

Ernest72 · 07-13-2023, 01:48 PM

If it’s just a DD car then changing early is overkill honestly. I changed the diff fluid at 30k and the stuff came out looking the same as what went in.

Have not heard of any blown diffs.

The tranny and engine oil, probably would change more often, depending on your abuse, but better yet get and oil analysis and know where you stand.

01-11-2023, 01:26 PM	#1
formulaBRZ Resident Grannyshifter Join Date: Oct 2022 Drives: 2022 BRZ w/ STI aero Location: PNW Posts: 20 Thanks: 35 Thanked 7 Times in 3 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Trans & Diff Fluid Change at 10,000mi? Hey all, I'm considering picking up some Red Line MT-90 and 75W85 gear oil and having a reputable independent shop perform a trans and diff fluid change at 10k miles. My idea here is similar to the philosophy of doing an engine oil change after the 1000mi break-in to flush any undesirable metals - However, I'd be doing the trans/diff after about a year of ownership. It seems the general consensus is that factory fluids suck, but would swapping to Red Line and flushing the factory gear oil provide any benefit this early in the life of the car?

01-11-2023, 01:45 PM	#2
OkieSnuffBox Senior Member Join Date: Aug 2014 Drives: '23 BRZ Limited Location: OKC, OK Posts: 1,986 Thanks: 660 Thanked 1,230 Times in 703 Posts Mentioned: 9 Post(s) Tagged: 1 Thread(s)	Yes. I probably would have done it sooner. I'm about to have the 1k mile oil change done on my '23. I plan on doing the trans/diff sometime between 1k-2k miles. __________________ "95% of the time, more throttle is the answer. 5% of the time, it ends the suspense."

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01-11-2023, 04:12 PM	#4
otter Senior Member Join Date: Jan 2022 Drives: 22 BRZ Location: Austin Posts: 121 Thanks: 18 Thanked 57 Times in 42 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Just note that the 2nd gen doesn't have the same trans fluid recommendations as the previous gen. It calls for LV - I put the Redline LV fluid in my trans at 5k miles. Haven't bothered with the diff yet (I'm at 9k).

01-11-2023, 05:00 PM	#8
formulaBRZ Resident Grannyshifter Join Date: Oct 2022 Drives: 2022 BRZ w/ STI aero Location: PNW Posts: 20 Thanks: 35 Thanked 7 Times in 3 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Much appreciated! On an anecdotal level, are you satisfied with the MT-LV as an improvement over stock fluid? Noticeable difference? Main area I'm looking for improvement in shift feel is during those low temp shifts - maybe the first 5-10 minutes of driving where I'm still babying everything.

07-13-2023, 01:48 PM	#13
Ernest72 Senior Member Join Date: Jul 2016 Drives: 16 Silver BRZ, 04 Silver WRX wagon Location: Rockland county, NY Posts: 1,411 Thanks: 182 Thanked 768 Times in 439 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	If it’s just a DD car then changing early is overkill honestly. I changed the diff fluid at 30k and the stuff came out looking the same as what went in. Have not heard of any blown diffs. The tranny and engine oil, probably would change more often, depending on your abuse, but better yet get and oil analysis and know where you stand.

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