best manual trans fluids

[pbm]

Originally Posted by skyactiv
Ford Motorcraft XT-M5-QS
It is a true PAO synthetic made in Germany and a favorite with Miata owners.
I have had Motorcraft fluid in my GTI well over 100K and it's excellent.
I was able to buy it cheaper at a Ford dealer after being disappointed what Amazon charges for it. I did ask the parts guy if he could give me a better price and he helped me out.
https://www.amazon.com/Genuine-Ford-XT-M5-QS-Synthetic-Transmission/dp/B000NUES82



The MTX-75 used in pre-2012 Focus's spec'd this fluid ....starting with the 2012 Focus they went with a 75W GL-4 although the tranny itself didn't change (to my knowledge). I am wondering how my 2014 5 speed Focus would do with this thicker MTF?

 

[Razorsharpe]

I have been quite happy with Redline manual transmission fluids. If they make something for the spec you require, I recommend you give it a try.

 

[AC1DD]

Originally Posted by skyactiv
Ford Motorcraft XT-M5-QS
It is a true PAO synthetic made in Germany and a favorite with Miata owners.
I have had Motorcraft fluid in my GTI well over 100K and it's excellent.
I was able to buy it cheaper at a Ford dealer after being disappointed what Amazon charges for it. I did ask the parts guy if he could give me a better price and he helped me out.
https://www.amazon.com/Genuine-Ford-XT-M5-QS-Synthetic-Transmission/dp/B000NUES82

Any idea which oil company makes this for Ford?

I figure it's possibly Shell, Castrol, or perhaps Ravenol

 

[Revving2Redline]

Ask Dave at Redline. Their MTL series is good stuff.

 

[zeng]

Any GL4 with higher KV40 than recommended ,never mind it be synchromesh or ATF .

 

[Cdn17Sport6MT]

Zeng, are you saying that you should use a product that has (slightly??) higher kinematic viscosity at 40C (~100F) than what is recommended by the mfr - so that rolling element bearings, gear-faces / flanks will be more protected ... at the expense of synchronizer life expectancy? If I have this right, at a certain point - any speed-gears that are running on needle bearings might suffer from the inability of the lubricant to get into those tight spaces... am I right, here?

 

[zeng]

Originally Posted by Cdn17Sport6MT
Zeng, are you saying that you should use a product that has (slightly??) higher kinematic viscosity at 40C (~100F) than what is recommended by the mfr - so that rolling element bearings, gear-faces / flanks will be more protected ..

Yes, for higher MOFT.

Quote
.... at the expense of synchronizer life expectancy?

Synchronizer life or shift smoothness is generally influenced by the ratio of Dynamic Coefficient of friction to Static Coefficient of friction of contacting surfaces.

Shift smoothness or synchronizer life is helped with a ratio of near 1:1, and may be unacceptable at ratios of 2:1 or 1:2 .

Unfortunately this ratio within a system changes with system linear speeds, system temperatures ,possibly loads,oil aging, viscosities etc inspite of one and only type of additives/friction modifier package being in use.

Hence a superbly 'good' MTF may have a bad moment or two of shift smoothness while in use in any manual transmission system.

However on cold-shift nuisance in cold ambients of yours , an MTF with a (very) low Brookfield Viscosity may help, IMHO.

Quote
If I have this right, at a certain point - any speed-gears that are running on needle bearings might suffer from the inability of the lubricant to get into those tight spaces... am I right, here?

While physics may suggest so, but before it occurs in a relatively low linear speed transmission system this phenomenon should have first happened in high linear speed environments say, in high speed gasoline engines in particular a 2-stroke engines at 6000,7000,8000 rpm regimes, but do we ??

Hence, that 'certain point' in time may never occur in real world transmission system applications .

Just my

 

[Cdn17Sport6MT]

Thank you for much more than your "2 cents"; a very well-considered response

.

 

[bulwnkl]

Best manual transmission fluids were from Specialty Formulations. After Molekule closed that down, the next-best were always Red Line products for me (mainly in Mazdas and Subarus).

 

[Coventry]

Penrite Pro Gear 70W-75 full syn GL-4 Plus. Pretty unique product.