I've been reading all over this forum about that topic and on the internet.
What are you guys running? Why you chose it? and which one is right?

From what I deduce:
1) MTL is lighter weight than MT-90
2) MTL less viscous in cold weather than MT-90 (easier to shift in winter)
3) MT-90 from the Redline website specifically mentions "as recommended in most Mazda transmissions". MTL states is for most Hondas.

Please help guys?

 

All of the guys that did fluid changes at my house used MT-90, its what I got from the Rotary Shop based in Sauga. It was pretty much the consensus on teh forum too, considering guys based in Chicago and New York were also using it, there weather patterns are pretty similar to us. I would have been weary if only the guys in the south were using them, but like I said consensus says MT-90. Also teh manufacture states to use MT-90, worse case scenario, your tranny goes bad, and its traced back to the fluid, you have a big cooperation like Redline to go after, not a bunch of guys on a forum.

My two cents.

 

Also, considering how hot the tranny gets, and considering you run your engine harder in the winter without trying, it being less viscous wouldnt really matter to me.

 

I drive my car hard sometimes.. i.e. 9400 rpm shifts in 1st, 2nd, and 3rd I also drive the car all year round, so winter shifting is important to me... should I still go for MT-90?

 

I would say so, its better than that OEM stuff or the Royal Purple stuff. Your doing hard shifts, but not till your engine is warmed up of course. Like I said general consensus has been MT-90, but in the end its your car, I dont like to deviate from the consensus, espeically since my powertrain is ending a lot sooner than yours.

 

Well I dont know about the places you guys have talked to about fluids etc. I deal with the guys who actually build and race these cars. Mazdatrix, Racing Beat and a guy named Roger Mandeville (if you google it he is the god of high performance rotarys and was doing them back in the late 70's until now). When I was going through stock gear boxes like crazy he was the one who told me why. He was the one who suggested I switch to MTL and lo and behold havent had a gear box since. We stock both MT90 and MTL, I will be happy to sell anyone which ever they prefer. I can only tell you from experience than the MTL is smoother and quieter in Mazda OEM transmissions than MT90. Your cars no matter how hard you drive them on the street will ever get close to the kinds of temps to any harm to the internals of your diffs or gearboxes. Just my opinion of course.

 

/\ interesting . what was his reasoning behind the failures with MT90 ?

I switched to 75w-120ns recently . Seems to be better than MT90 or LW shockproof for track duty .

 

The LW or HW shockproof is not for use on syncromesh transmissions! I learned that after transmission #4. It really helps to read the label lol. The MT90 is heavier than the MTL, the gears in Mazda transmissions especially in older one are only designed for about 150 rwhp and 120ftlbs of torque. The heavier fluids are harder to push through the gear, Im sure you get the picture from there. The RX8 trannies are much beefier than the older ones, but still can be helped by the MTL for smoother operation, better shifting and better fuel mileage. Thats part of the same equation for 5W20 engine oil rather than 5W30 etc. It is the racers oldest trick in the book..................lighter fluids make more horsepower......of course there can be some drawbacks in a racing application lol

btw: ns on a label mean "non slip" in most cases and is for rear gears that are not limited slip. I would recommend removing it from a transmission or limited slip differential if it actually a "ns" product. That product is designed to make things stick together and act more like a limited slip unti which is something you really dont want in your transmission.

 

If MTL is the lighter fluid, in the summer time, wouldn't it cause the transmission to overheat? The OEM fluids in my car now is already making the centre console quite hot.

 

see:
The oil isn't coolant and doesn't factor in the temperature of your arm rest. It doesn't make your transmission hot. Some oils stand up to heat better than lighter oils.

 

AL: "I would recommend removing it from a transmission or limited slip differential if it actually a "ns" product. That product is designed to make things stick together and act more like a limited slip unti which is something you really dont want in your transmission."

Pros, did we put NS oil in our diff at your place?

 

QTWRE,

Oil helps carry heat away from the surfaces of the gear.

 

Scott, no worries aout the gear oil, Al carries 75W90 for the diff at the Shop too.

 

FOOTMAN,

Are you saying you want oil that keeps the heat on the gears so that it doesn't heat up your console? :P

 

We dont carry the "NS" here, we only bring it in for special orders.

 

QTWRE,

No.

 

When I bought my car two months ago (2004 6speed), I changed the differential, transmission and engine oils within the first week. I'm running the Red Line MTL and the 75w90 in the transmission and diff respectively. I almost knew the original oils were still in the car and all the break-in period particles were floating around. Besides not running OEM Spec engine oil, I choose the Red Line series because I heard great things about them from both this forum and friends with with more sporting cars.

 

Sanguine,

Why did you choose MTL for the tranny?

 

I'd say get the MT-90 but the place I bought it from, some Rice/Race place in Mississauga, didn't have MT-90 in stock and I couldn't find it anywhere else reasonably close. I know this is comparing apples to oranges but I have a friend with a RSX-s and he runs the 70w80 MTL all year.

I would say stick with the Mazda spec 75w90 MT-90. I'll let you know if my transmission implodes though.

 

The MTL on the Redline website says it's suitable for Honda (hence RSX) applications, whilst the MT-90 is suited for Mazda (75W90 spec)

 

Yeah, you can't go wrong sticking to the Mazda spec MT-90. The 70w80 MTL is a bit thinner and trouble could arise from that. During the winter just take it slow with whatever you choose. I live in a sleepy little neighborhood with a quite a few stop signs so I always get an easy 2 minute warm up before hitting a real street.

 

Ya, I believe the MTL is 75W80, and MT-90 is 75W90.

 

I tried a few different oils early in my ownership - went from OEM to MT90 and found it a lot thicker, especially at startup in cold weather - like syrup.

Tried the purple stuff and some Valvoline Synthetic and Castrol 75w90, but eventually went back to MT90 with about 25% MTL mixed in (seems MazdaManiac uses the same mix!) and have run it for the past four years, with zero problems.


S

 

MTL is 70W80

 

mixing... hmm... why mix? Is it cause straight 100% MTL alone is not protective enough?