MT-90 from Redline
 

Just changed the diff and tranny fluid at 36k. There is considerably a huge difference in the way that the car shifts. Just wondering how everyone elses experience is with the oil, and trying to inform the people that haven't used it to swap. My car now shifts like butter, and thats an understatement. :driving:

I changed mine out using redline at 3500 miles due to buying the car with 2500 miles on it and not knowing how hard it had been driven before. I am now feeling somewhat of a light vibration in the stick shifter and pedals. I changed the fluuds myself and feel confident everything was done correctly but have that nagging feeling that maybe just didn't get enough fluids in.any thouhts or is anyone else experiencing this vibration? The car is an 2009 base model w

Actually, the recommended Red Line fluid for the MT 370Z is MT-85.

You are correct i forgot to mention that i had to special order from my local race shop to get this blend for our Z's

Correct, but I've now heard from two people that MT-90 performs great in our transmissions. I had Redline's MT-85 in mine and it had a very notchy 1st to 2nd shift. I switched back to OEM mt oil and the notchiness is gone. I wonder if Redline's 85 weight is actually a little thinner than the 85 rating it shows.

I've run multiple fluids through my 350Z/G35 and 370ZG37 transmissions for testing including 3 of the Redline MT oils both straight or in mixes.

Here are my observations.

1.) Redline MTL 75W90 straight
Felt good when cold, shifted smooth without notch under normal driving until you pushed it hard. Once the trans started getting hot it would get notchy quick and you could feel slight gear nibble at high RPM before it meshed the next gear. Down shifting was ok but no significant improvement over Nissan fluid.

2.) 50/50 mix MT90 and MTL
A little notchier then straight MTL in the morning for the first few blocks but warmed up quickly giving nice smooth shifts. When pushing hard or on really hot days it maintained its good shifting qualities with very minimal notch at high RPM. Downshifting was much improved once warmed up over MTL or Nissan fluid. Cold downshifting was somewhat worse then stock or MTL.

3.) MT85 Straight - No surprise here it performed pretty much exactly like #2 the 50/50 mix as that is all Redline has done to make its in-between formula.

4.) MT90 Straight-
Much notchier then straight MTL in the morning and takes longer to warm up. The colder it is overnight the worse it’ll be. Once warmed up it shifts like butter. When pushing hard or on really hot days it maintained good shifting no matter how hard you pushed. Downshifting was exceptional once warmed up over MTL or Nissan fluid. While cold the downshifting was much worse then MTL.

I wouldn’t us straight MT90 unless you live where the temperature remains fairly high year round so warmup isn’t as much of an issue or if you track the car regularly. Definitely not for cold weather use.

I’ve also tried the following mixes:
2 quart MTL + 1 quarts MT90 which is not as good as the 50/50 mix.
2 quarts MT90 + 1 quart MTL which is a better alternative for a mainly street driven car then straight MT90.

Now for the not so mainstream answer and for the best shifting fluid I’ve ever come up with for all weather and all purpose use... I mix 1 Quart Redline MT90, 1 Quart Redline MTL and 1 Quart of Amsoil Synthetic Synchromesh Fluid. This mix was tested in both my 06’G35 and my 09’ G37 and the results are like the best of both worlds. No notch when cold, no notch when hot or pushed hard, buttery smooth up shifts and really nice downshifts even if you’re lazy and aren’t rev matching. The synchro’s seem to love it as they quiet down and just all around seem to function faster especially when cold and on downshifts. Also zero grinds and upon draining at 5k miles there was no tell-tale synchro glitter or metal particles to indicate anything other then a healthy transmission.
Take with grain of salt and try at your own risk.

Also before someone asks me about our cars taking 3.2 quarts of fluid I’ve always used 3.0 quarts for changes as unless you leave if to drain for days you’ll never get that last 0.2 of a quart out and the 3.0 has always easily gotten me to the full mark when level… so no need to waste money buying a 4th bottle of fluid.

Thanks for that very informative post Ryan.

I've only tried MT85 and OEM so far. I was thinking (and this might sound like I'm over-thinking) about mixing MT85 and MT90 to get a ~MT88 type of blend. I already have a few bottles of each laying around so I might just test it out over the holidays.

I believe this may be what you did here, when you say quote:

I’ve also tried the following mixes:
1 quart MTL + 2 quarts MT90 which is not as good as the 50/50 mix.
2 quarts MT90 + 1 quart MTL which is a better alternative for a mainly street driven car then straight MT90.

But it seems like these two blends would be the exact same thing right? They are both 1/3 MTL and 2/3 MT90 fill.

Mandingo you're welcome.
Looks like I goofed typing those mixes though.
They should have read:

2 quarts MTL + 1 quarts MT90 is not as good as the 50/50 mix.

2 quarts MT90 + 1 quart MTL which is a better alternative for a mainly street driven car then straight MT90.

So yes, 2/3 MT90 and 1/3 MTL should give you a little better hot shifting over the MT85 while not being as harsh as MT90 in the morning when cold. While I haven't tried it I'd think the 2qrts MT85 and 1qrt MT90 should be a pretty good combination as well.

I just had Amsoil Synthetic 80W90 done to the transmission, and when it's cold...the car will hardly engage a gear, it's waaay too harsh. Shifting from 1st to 2nd, you can feel the transmission doesn't want to let go of the gear (I guess this is the "nibble" effect?).

Once it warms up (about 5 minutes or so), it feels absolutely great and buttery. But this is definitely not a cold weather weight. I wish I had known that before telling my shop to go ahead. I am moving to Florida in 2 months, so perhaps I should just wait it out?

Perhaps pouring a little of the Amsoil out and mixing with OEM would make this a more optimal weight for colder days?

Used mt 85, transmission felt good for less than a week. Now it is like poop again

I have to chime in here - I'm reconsidering options as I'm not at all impressed with Redline in my tranny or diff. I just changed it and have only put around 1000 miles on the car since. Used MT 85 for tranny and 75w90 for the diff. I'm going to go Motul and possibly sooner than later.

The car honestly feels no different after getting rid of the fluids at 30,000 miles. The diff fluid was almost completely black too.

its normal for the diff fluid to be that dark. it only has 2.5 to 3 qts of oil in it right? think about how many miles that is. I used mt90 for the trans and I have noticed since it is colder that it is a little bit harder to shift due to the fact that it is cold....but it is something that I tolerate because most of the rest of the year it is warm here. to each their own.

I just used redline mt85 for my trans and redline 75w90 for the diff and find the mt85 pretty good for me here in Richmond VA. We get all 4 seasons but not real harsh in any particular season either. I maybe put 5k on my car a year so I do quarterly oil changes and yearly trans and diff changes just bc it's cheap and don't drive far. @ Zbro16 and at 30k to have black diff fluid is pretty common especially with the LSD. If you drive your car hard I would def get yourself on a more frequent interval especially if you track your car bc I'm pretty sure at the 30k interval it's gonna be pretty dark regardless the brand of fluid you get

What's wrong with OEM fluid? Especially if it's shifting fine as it is?

In my car it shifted like crap compared to redline. I really noticed the difference especially after getting the trans warmed up, it never notched or grinded from 1st to 2nd. Where as with the factory oil it grinddd almost every time!