What is the best Manual Transmission Fluid?

Discussion in 'Fuel Economy' started by Shan, Nov 23, 2008.

  1. Shan

    Shan SGII Equiped FIT Driver....finally!

    I have a 2007 Honda FIT.


    What do you recommend for better mpg?

    I was going to stick with Honda MTF; however, I use 0w20 Mobile 1 synthetic for the engine.
     
  2. kendan

    kendan Mid TN Hypermiler!

    What your tranny takes is Extended life Dextron ATF. There are no thinner grades or more FE grades available. This is pretty thin fluid already and is used specifically because it is more efficient than the 80 weight gear oil that used to be used in manual tranny's. As for brands, you want to go with the best extended life fluid because fluid breakdown will damage your tranny.
     
  3. Shan

    Shan SGII Equiped FIT Driver....finally!

    So, if I am understanding you correctly, I should just stick with Honda MTF? That was my original plan but I wanted some other opinions from the pros here and what they use.
     
  4. Kurz

    Kurz Well-Known Member

    http://www.amsoil.com/a/synthetic-transmission-fluid

    Just pick the one with the right specs.

    I've heard from 8th Civic SI drivers it treats the problems with their six speed transmission.
    Honestly this could be the best Fluid for anyone. From many feedback it also treats notchyness.
     
  5. some_other_dave

    some_other_dave Well-Known Member

    Check the owner's manual for your Fit. It will tell you what is "recommended" (for a manual transmission car, that's most likely Honda MTF), and it might tell you what else is "acceptable".

    Some recent manual transmissions do call for ATF (Auto Trans Fluid, which is what kendan was recommending), but some do no. It would be a big mistake to put ATF into a trans that requires MTF, likewise putting MTF or motor oil into a transmission that requires ATF would also be bad.

    My old 1990 CRX (Civic) lists 10W30 or 10W40 motor oil as the correct transmission oil. Honda used motor oil in their transmissions for many many years; my mom's 70s-vintage Civic called for it as well!

    If your owner's manual calls for motor oil, I would use a good quality non-synthetic one of the thinnest weight recommended. And that's about all you can do for transmissions. I specifically mention non-synthetic oil because the synchros "like" a certain amount of drag and friction to work properly, and synthetic oil can be "too slippery" for good shifting. Transmission fluids will often have additives that "work with" the synchros correctly, and newer cars also tend to have transmissions that are synthetic-fluid-friendly.

    -soD
     
  6. Shan

    Shan SGII Equiped FIT Driver....finally!

    I agree with that which is why I did read the owners manual at lunch to find out that it recommended Honda MTF but you can use 10w30 oil as a "temporary" solution until you get HMTF. Supposedly there are not enough additives in the 10w30 for a permanent fix. Which made me continue my trip to the dealership to purchase the HMTF and to my surprise the MTF said new formula for smoother shifting and better fuel economy. I hope that is not a gimmick, especial at $5 a quart but then again I only had to purchase 2 qts since it only holds 1.6qts.
     
  7. some_other_dave

    some_other_dave Well-Known Member

    A couple words of warning:

    Always remove the fill plug before the drain plug! That means that a stuck or stripped fill plug will still allow you to drive to a shop with Big Powerful Tools, rather than having to tow the car there.

    Next, make sure that the car is level when you fill up the transmission fluid. If the front is on jack stands, the car is not level, and the fluid level will be wrong. If the level winds up being low enough, your Input Shaft Bearing (ISB) will slowly self-destruct, at least if your transmission is anything like those on the older Civics.

    Guess how I know that, and why I'm on my second transmission with this car??

    -soD
     
  8. Shan

    Shan SGII Equiped FIT Driver....finally!

    LOL! I understand that completely. I have done a couple of Honda motor swaps and pulled the tranny off my integra motor several times. However, I never thought of removing the fill plug first, good point. With this being a new car it better not be a problem! :p In the past for tranny fluid I have used either HMTF or Penzoil Synchromesh(because of grinds) but this is the first time I am actually doing this to help improve mpg. :p
     
  9. msirach

    msirach Well-Known Member

    Amsoil has a manual transmission fluid specifically designed for Honda hybrid syncromesh transmissions.
     
  10. Shan

    Shan SGII Equiped FIT Driver....finally!

    Fresh oil change and Fresh tranny fluid change, the FIT is GO! I swear it shifts much better. With the skunk2 short shifter I noticed a bit of notchy shifty but since the tranny fluid change I have not noticed any notchy shifty, Honda MTF FTW!
     
  11. Kacey Green

    Kacey Green Well-Known Member

    The Fit is always go! :D
     
  12. Ronbo

    Ronbo Member

  13. Kurz

    Kurz Well-Known Member

    Just remember its the same fluid that was in the tranny in the first place.
     

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