Liking the MT-90 so far
 

Very happy with the results of the MT-90 especially with the colder temps here in Virginia, though probably not as cold as Minnesota or Michigan.


Thank you @Goingnowherefast for the heads up about Ford's Motorcraft XT-M5-QS GL-5 MTF!!


2017 Subaru BRZ Owner's Manual pages 475-76 refer to the oils usable in the rear axle and the Manual Transmission. (See pics below).


Since Subaru has okay'd the use of GL-5 in the transmission, there shouldn't be an issue, though countless manufacturers of GL-5 oils do not recommend it for our transmission (due to the copper and bronze rings).


For now, I am happy with the results of the Red Line MT-90 (sounds like @MotoX16 is as well) and will see how long it stays reliable, but will probably switch over to the Motorcraft XT-M5-QS GL-5 MTF. After doing a quick Google search, it seems that this stuff is being recommended on a variety of car site forums.


Thank you guys for the input!

I'm going to get an analysis done on my gearbox oil at Mainlube in Botany, Australia when I change it out.

I'll drop off the sample to them, it will take 30 minutes for the test and evaluation, from there we will make a call of what is required.

Mainlube can decant a mix on site for me.

Mainlube have a really good name with their oils, choosing oil weight and required additives here, their oil is quite expensive but they build oils for alot of raceteams, heavy plant and industry.

I only need to grab 2.5ltrs of the stuff so additional cost isn't a worry.

They build their oil packs based of the analysis, type of metals used and the use of the equipment.

I'll post up when it's done, give me a few weeks.

I think this is a different process to Blackstone, but if it's good enough for heavy industry and race teams, it's good enough for me.

https://www.google.com/url?sa=t&sour...WIKIXS_zCTWs6-

Imagine what difference the MT85 made compared with the Gear 300 I had before!
Along with the Mtec shifter springs the difference is so big that I don't feel the shifting is different from any other good JDM gearbox I have tried including MX5 that has a very good gearbox for my taste.

Nice! I will definitely be awaiting your results as well as checking out a place like MainLube that does testing here in the States.

I believe its called "Blackstone".

Yeap > https://www.blackstone-labs.com/

Edit: maybe, maybe not, their testing process are apparently different.

After a couple of weeks
 

After having the Red Line MT-90 in for almost 2 weeks and going thru some drastic temperature changes here, I coming to the opinion that there really has not been that drastic a change between the previous fluid, skipping the results of the Subaru GL-5, and the RL MT-90. Yes, on the colder days the shift into 2nd gear has not been as bad as before, I have had a couple moments where if I didn't double clutch or use my little"drop" into neutral then into 2nd, I did catch a little. But once the transmission oil has warmed up, no issues.


I think if I was living further North I would definitely try one of the oil pan heating pads on the transmission. Maybe as next Winter gets closer I'll get one and see how it goes. Going to be 70° here tomorrow and better weather on the way.


If anyone who will be in the winter months a little longer tries out one of the oil pan heating pads, let us know how it goes. Thanks!

My 1 year account of Redline MT90

After 2 winters I switched from the factory fluid to Redline MT90 in my 2017 BRZ. I have had the car since it new so I know its history and do not flog it senselessly.

Like many of you, I found the transmission to be gritty enough that it felt like I was stirring a bag of gravel when shifting from first to second gear during temperatures around 0 celcius. The consensus of the internet was to either try Motul 300 or Redline MT90.

The decision to choose Redline was down to most of the feedback from owners stating that it was better in cold temperatures and availability at Part Source.

April 2019: with 26500 km on the odometer, I lifted the car and changed transmission fluid to Redline MT90, and the differential to Redline 75W85 GL5. I made sure to overfill and let the excess drain out. The levels were good.

On the initial drive after changing the fluid, I wanted to say it was much smoother, but honestly speaking, it was marginal at best since ambient temperatures at that point were closer to 10 celcius. So I drove the car like usual, took it to a couple of track days at TMP for the rest of the year. No issues with the fluid, business as usual.

October 2019: I had driven 10000 km with MT90 and switched over to a new set of winter tires. Flurries were beginning, I was ready for the winter.

Typically, I leave my car parked in a covered garage at work, temperatures would consistently stay below 0 for 9 hours a day so this was a good test. I have put on about 6000 km of winter driving since October, and I am happy to say that the shifts from first to second are much smoother and takes less force to shift compared to the factory fluid when driving from a cold state. After about 2 minutes of driving, it feels like business as usual.

Overall, I would say it's worth a shot.

Sent from my SM-G970W using Tapatalk

THANK YOU, Ktse!! Good to have some feedback from other users on this!


Think I have added only about 150 miles to my BRZ since putting in the Redline MT-90, and I agree with you 100% that it is better than the Subaru oil. On super cold mornings, there have been a few couple times of rough shifting in to 2nd, but again few times and once the transmission has warmed up, everything is fine.


Still, considering @Goingnowherefast's recommendation of the Ford Motorcraft XT-M5-QS GL-5 MTF. Maybe in an other 25,000 miles I'll give it a shot. But for now, totally happy with the MT-90.


Again, thank you Ktse as well as any of the other BRZ owners up North! I appreciate your input.

TLDR:
- 30k (miles) - Do not recommend Valvoline 75w90, especially with LS additive containing fluid for transmission or differential (don't need it).
- 60k - Amsoil 75w90 - good stuff, but not satisfied
- 90k - Synchromesh, pretty good stuff, even in warm weather.
- 120k - Willing to try Redline GL4 75w85 stuff

Just to chime in, I've had a variety of fluids testing for my FR-S transmission and differential. I'm nearing my 120k (mile) mark transmission fluid change as I write about it before I try Redline.

NOTE: My ambient temperatures range from 60 to 100°F, so it will not necessarily apply to most of you folks freezing your nuts off. Most of my reactions are from transmission issues; no gripes from differential, but fluid change also improved its operation a bit (quieter).

Valvoline 75w90 LS and (briefly) Synthetic 75w90:
One dealer had swapped fluids around 30k, but I wasn't happy with their choice since although being better than the initial Gunma Japan fill. Not completely happy since it didn't crunch 2nd gear as much, but 3rd and 4th were occasionally picky.

Nearing 60k mark, I asked dealer what fluid they would use for next change, and told me same one as already in use. It ended up being an 75w90 LS (limited slip additive) product INSIDE TRANSMISSION. So, not only did I had that fluid dropped, I also dropped dealer. After going to another dealer and having the TOB replaced under warranty, they swapped to a Valvoline 75w90 synthetic. Not happy still (it still crunched 2nd gear as well as 3rd and 4th occasionally), I swapped to Amsoil 75w90 GL4 on my own after the 60k mark.

Amsoil 75w90 GL4 / Amsoil Severe Gear 75w90:
I was much happier the way the FR-s transmission was feeling, but it still didn't feel perfect. Kept it for 30k miles since it still felt significantly better than previous fluids.

Pennzoil Synchromesh / Amsoil Severe Gear 75w90:

I've been using some Pennzoil Synchromesh fill on my transmission, after using Amsoil MTF for a while (still using Amsoil Severe Gear 75W90 on differential). Its the best feeling I've received from my car, since it goes into any gear with relative ease, including going into first gear without a dead stop. It is much better going into gear than with previous fluids, especially in cold weather. Alas, it is a much thinner fluid than needed. I did so because after all, my car was already out of warranty.

Buenos Dias y muchas gracias por tus hallazgos, @sato!!


I'd almost trade my weather for yours, except the whole hurricane thing. And I do hope that you all are recovering well from that last big one in 2017.


It's always good to get info on any of the different climate conditions. I'm happy with the Redline MT-90 in my transmission at the moment. We'll see how that does in a few more months as the heat increases here in Virginia. Definitely keep us posted as to the changes you make as the miles accumulate on your FR-S. I'm sure there are plenty of owners with higher mileage vehicles that will appreciate the guidance of what you have been thru.


Nuevamente, muchas gracias y sigan enviando la información...

Saludos and thanks for caring about our past (Irma/Maria): we are still recovering, but will eventually pull thru. Some are having a lot worse time than me, but I'm guessing we are resilient people, even if we b!tch about it.

In regards to the high mileage info, you are welcome! Its mostly highway miles for me, but still seemed like a nice thread to dump my info in, while feed on info for my transmission fluid change. Keep us posted.

I forgot to mention, I was also interested in the Amsoil Manual Synchromesh Fluid, but at $35 bucks @Amassson, I will probably stick with Redline as my next choice. Anybody tried that one?
https://www.amazon.com/Amsoil-Manual.../dp/B019GEZC1C