Questions related to Petosin MTF-2 Transmission Fluid
 

Hello FT86s!

I decided to change transmission fluid because Im having problem shifting 1st to 2nd gear. So, I ordered Petosin MTF-2 a week ago and I just got 3 bottles of them today. I chose Petosin MTF-2 because I saw lot of posts that these are really great products for cold temperature. Because I live in northern area of Indiana, I have been having hard time shifting gear since winter came. The weather is getting better, but shifting 1st to 2nd is still not smooth at all. I have to put some force on it and it makes grind noise when it shifts to 2nd from 1st gear.

Anyway, my point is, how is MTF-2 fluid in high temperature? I know MTF-2 is a thin oil and I wasn't sure whether it is good or bad in high temperature. Summer in Indiana is around 82-90 degree Fahrenheit. My brz is for daily drive and not be used for track at all. Any idea or suggestion? Should I just hold on them and change fluid on winter?

Thanks for reading!

Thanks!! :D

I put Pentosin in at 6000 miles. Ran it until 30,000 miles and refilled it again with Pentosin. Going on 46,000 miles now and no problems. I live in south Texas, and last summer had many 100+ degree days and. Mine is a DD also. I'm planning on changing it @50,000 miles. I'll go back with Pentosin again.

I'm personally not comfortable with running a fluid that has roughly half of the viscosity of the specced fluid at 100C.

Has anyone looked into average transmission fluid temps during hard driving at moderate to high ambient temperatures?

I'm personally trying the motul first, but I'm on my way to a long hot summer here in the desert.

I am very curious about the Ford motor craft "honey" that the miata guys rave about for the nb and nc six speeds. It's specs from Ford make it look like great stuff, but I've found a lot of conflicting info on its actual properties on bitog. Some say it's made by Fuchs, some say castrol, the ford data sheet I found says viscosity of ~15 at 100C but other sources say it's more like 10 ( including molauke) and basically a diesel motor oil.

By the bottle specs, it seems perfect. High VI, thin at lore temps, gl4, specifically for transmissions, and 75w-90 spec for warranty. But that doesn't line up with what molauke or big Jim say about it on the forums over there.

Cheers
Nathan

Transmission oil should not be thick. Don't let 7-14 cSt at 100C scare you. It's ok.

Yeah as an example, the 6MT GM Transmissions use ATF in them (CTS-V, Camaro, Corvette, etc) and that stuff is very very thin.

-mike

You can't just say "x or y transmission uses atf so thinner fluid is okay." Those transmissions were designed for atf. Go put atf in our transmission and let me know how that works out in the long run. Things like oil passage size, syncro areas, etc are all based partly on the designed for fluid viscosity at operating temp. Dropping from ~15 cP at 100C to 14 or even 10 (something like redline mtl or mt-85) I can see but cutting that value in half? Doesn't seem so great unless the transmission is designed from the start to use such a thin fluid.

It goes both ways. BMW transmissions call for pentosin mtf2 from the factory. I wouldn't put a 75w-90 into one of them and expect it to be any good.

Cheers
Nathan

I never said to put ATF into the transmissions of these cars. I was MERELY using it as an example of a high performance car that uses a thin fluid.

-mike

Thank you for sharing your experience:thumbup:

The engineers were asleep at the wheel when they spec'd the factory fill. Enjoy Pentosin. I know I do.

Been running it for about 20k miles. But changed it after 15k and track days to send in for UOA. (Northern Illinois)

I have zero issues with 1-2nd shifts When cold below 30, 1-2nd is a bit notchy for about 5 minutes. I never downshift to first unless I am below 5MPH.

In many threads I said this, these transmissions are inconsistent. In your case if Pentosin is still not smoothing out your 1-2-3 shifts after warm up your gearbox is flaky and thats just how some of them are.

I got the word from the man Molakule himself. Pentosin MTF2 should be fine in our transmissions:

http://www.bobistheoilguy.com/forums...on#Post3364612

It's on my list of things to try (mine really isn't that bad to begin with, I have a garage, and it's currently going into summer in the desert), but for now I want to stick with the factory specced viscosity. I've got about 10k to go before my drivetrain transfers over to the extended warranty and I want to keep things in spec for at least the duration of the standard 60k powertrain, just in case.

I'm personally going to try the Motorcraft fluid all the Miata guys love. Similar cost, specifically formulated to deal with problem syncros (Ford had a shitstorm of them with the Getrags in the foci), the miata transmission is similar to ours (Aisin), same viscosity as our factory fill and GL4 rated. It's specs put it in the quality realm of Motul 300 (similar VI and flash point). MS3 and other FWD guys like it as well and many of those cars are known to have crap syncros that are even worse than ours. It's made by Fuchs in Germany so you know the quality is up there.

According to a lot of reading I've done, in moderate temperatures shift performance is less driven by viscosity and more by the friction characteristics of the fluid. Good MTF has friction modifiers that as the synchro cones/teeth/whatever this tranny has get close, the friction ramps up, making the syncros job easier. This is one reason GL5's are in general suboptimal for syncros, they're designed to coat the surfaces in such a way that when things are in close contact and under a lot of shear (such as in a hypoid differential gear) things remain uber slippery. This coating interferes with the syncros' ability to match, slowing down the rate at which they can match each other's speed. Even if the newer GL5's are designed not to eat away the yellow metals in the syncros this should be reason enough to seek out a more optimal fluid (Such as the Pentosin, Redline, Amsoil, or Motorcraft GL4's)

I'll report back with my findings. More options are always good and word on the forums for many, many other cars is excellent for the Motorcraft FSMTF. (The thread about it on Miata.net has about 100 pages of people raving about it.)

TLDR: For those not wanting to vary from the factory specced viscosity, this Motorcraft fluid may be an option. Designed specifically to fix syncros that were costing Ford a ton of money. GL4, 75W90. Spec sheet here:

https://www.fcsdchemicalsandlubrican...on%20Fluid.pdf

Cheers
Nathan

Let us know on the Ford oil, for now I'm very happy with Pentosin.

FWIW........I just replaced with Motul and so far, I hate it. Huge degredation from the stock fluid.

Yup probably had same experience as me then. As it's been discussed works good for some but not for all due to likely tolerances. The MTF2 feels great in mine, give it a go.