By on January 15, 2010

Transmission complete? (

Anonymous writes:

I love this column, great advice every time. That’s why I decided to ask for your opinion on something that’s been bothering me for a while. I have a ’07 Mazda3 hatchback with a 5-speed manual. Currently I’ve crested 23,000 miles and the car is still under warranty.

Ever since I bought the car (brand new), the shifter has been a bit notchy going from 1st to 2nd. It could also be smoother from 3rd to 2nd. Another thing that bugs me is that during our cold Chicago winters, until the car/transmission warms up, the shifter is very mushy and stiff. Otherwise, the car is a blast to drive.

So I’ve read a bit about GM’s Synchromesh Fluid and from what I hear, it does wonders and it should fix my problems if I were to swap my transmission fluid. Now here are my questions regarding this:

1) In your opinion, do you think I would really feel the difference: much smoother shifts all around and easy shifting in cold weather? Or is it just a placebo effect?

2) My Mazda dealer wants almost $200 for the fluid swap with their own fluid. For various reasons I can’t do it on my own and I don’t feel like trusting a 3rd party mechanic. The dealer has been fairly trustworthy so far. Do you think it’s a fair price? Would it make more sense to bring my own fluid, such as the Pennzoil Synchromesh sold by Autozone?

3) Should I be concerned that the dealer might use regular fluid instead of Synchromesh? I believe they are honest but you never know and the customer is not allowed in the shop anyway…

I would really appreciate a good suggestion for this dilemma.

Sajeev Replies:

Question 1: to reiterate, I noticed a significant improvement in shift quality with a fluid change to GM synchromesh. Then I noticed a minor improvement with said fluid swap on another vehicle. Either way, I think it is a win. And you don’t have to buy the bottle with GM’s Mark of Excellence, but theirs seems like a good value. The last time I priced checked, of course.

Question 2: That is a somewhat-fair price, but now’s the time to trust a third party mechanic. Look for one with a clean shop, loyal customers to a veteran shop owner and a computer with access to on-line service information systems like ALLDATA.

Question 3: There’s a good chance the dealer will use your fluid, because you (a smart consumer) only pays for labor. Then again, they may flat-out refuse to use non-Mazda fluids in your car. If so, refer to my answer to the previous question.

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28 Comments on “Piston Slap: Zoom Zoom, Mesh!...”

  • avatar

    Call me a cynic, but I would expect to void any future warranty on the tranny if you switch to something other than OE. That might be a calculated risk in exchange for better driveability, but since the car is under warranty, why not just take it to the dealer and see what (if anything) they’ll do about your shifter complaint? Even if you come out of pocket, $200 doesn’t sound bad to me at all for dealer service. They might even agree to non-OE fluid, but be sure to get paperwork saying they’ll warrant the work and tranny. That might be a longshot.

    Otherwise, I’d say wait until the 3/36 is over and do whatever you’d like! I’ve personally had great luck with Redline MT90.

    • 0 avatar

      The odds of synchromesh being detected as a fail point during the warranty period is highly unlikely, unless you abuse the heck out of your transmission and draw a lot of attention to yourself at the dealer.

      Not to mention the Magnuson-Moss Warranty Act is likely to cover synchromesh products branded under a famous name.

    • 0 avatar

      I’m with Ash78 on this one.

      Would sticking with the OEM fluid until the warranty expires cause any damage to the transmission?  If not, and the only problem is a notchy/sluggish shifter, I’d stick with the OEM for now just to bullet-proof your warranty.  Switch to synchromesh after the warranty expires.

    • 0 avatar

      I noticed the same problem in my ’05 Mazda3 hatch, 5-speed manual.  I switched to MT90 (did the work myself) about 7,000 miles ago and it did NOT help, in fact it might be slightly worse.
      I was thinking about trying Syncromesh, so I’d love to hear an update on this post.

    • 0 avatar

      If he doesn’t have the dealer do it, Mazda has no way of finding out what fluid hes used. It’s not like they test the chemical make up of the fluids in the returned transmissions.
      If the dealer does it, and doesn’t say anything about the warranty ahead of time, they still have to honor it. The dealer is supposed to be your resource on the matters, and if they allow you to use Synchromesh they have basically endorsed the product.
      If the dealer doesn’t do it, and warns you that it will void the warranty, you can still take it elsewhere and they can’t find out as long as you don’t tell them.
      So my advise would be to use whatever fluid people on the Mazda boards recommend. There was a cocktail of fluid that was all the rage on the Subaru boards where you would use a couple quarts of synchromesh and a couple of something else, I think the MT90. Look at what the people say for smooth shifting.

    • 0 avatar

      There was a cocktail of fluid that was all the rage on the Subaru boards where you would use a couple quarts of synchromesh and a couple of something else, I think the MT90.

      (actually laughing) – it’s not that I disagree, it just strikes me as really funny that someone took the time to think this up and try it . . . my kind of people ;)

    • 0 avatar

      I think the idea came from the Synchromesh being too sticky for the front diff, and the gear lube being to slippery for the synchros.

      EDIT: I found the mix. They call it Uncle Scotty’s Cocktail. Here is the 87 page thread

      Here’s the mix:
      1qt Redline lightweight shockproof
      1qt Pennzoil Synchromesh
      2qt Castrol HypoyC 80w-90

  • avatar
    Cammy Corrigan

    I own a Toyota Yaris and I spoke to my mechanic who services my cars. I asked him whether, when it comes time to change my tyres, could I use Pirellis instead of the Goodyear’s which the car came with from the factory and he summed it up beautifully:
    “I can’t speak for manufacturers like Ford, GM and Volkswagen, but when it comes to Toyota and Honda, always stick with what they recommend. If the car came with Goodyear tyres from the factory, stick with them. When Toyota or Honda pick a supplier, they’ve tested them rigourously to make sure they’re the part for the car. They don’t just pick the cheapest supplier. Likewise, when it comes to fluids, for the car, pick the car maker’s approved make, not one which ‘meets the standards’. That way you solve 2 problems: 1. you won’t invalidate your warranty and 2. the car will run the way it’s supposed to”.
    So far, he’s never been proved wrong when it comes to automotive mechanics.

    • 0 avatar

      I’ve never heard that before.
      The Bridgestone Dueler H/T D684 was possibly the worst tire ever put on an SUV.  He’s giving Honda way too much credit.

    • 0 avatar

      Yikes. That mechanic is mad. By his logic, winter tires would be a no-no.

      I keep my cars fairly stock, but I upgrade the tires and fluids. Never had a problem. 

      The crunchy 1-2 shift in my Miata was greatly helped by switching from OEM to Redline synthetic, by the way. Shifts better in the cold, too.  

    • 0 avatar

      Honda, Toyota, or any other manufacturer use whatever name brand tire they get the best price on.
      With that logic, the rollover Firestones are the best tires for the Explorer.

    • 0 avatar

      Yeah, that makes very little sense when compared to what I saw when I bought my last Honda: new Civics with both Goodyear and Firestone tires, side by side.

  • avatar

    ash78 — re: warranty
    They have to specify some standard; whatever that is, as long as he sticks with it, he should be protected.
    Anonymous —
    The “until warm” thing is normal for Mazdas.  There’s been a lot of questions about the 2009/2010s about the web and this — I only started noticing it on mine recently.   The wife’s tribeca sits out in the cold always and starts like a champ . . . my 6 on the otherhand only comes to life after doing a dead-seal bark (not problematic, it just sounds sick).  I’m assuming this has something to do with fluid viscosity . . . I wonder (out loud) what they use up in Yellowknife . . . has to be different oil/tranny fluid.
    I’m also sort of curious as to what you’re comparing the lower gears to.  I went GM->Honda->Mazda, so mine seems very buttery to me (nicely so) – any chance you can take a 2009/2010 Mazda6 for a spin at the dealer for comparison?
    My only complaint about shifting (not so much now) is that I went from a 2003 CR-V with a RSX short-shift kit installed to my 2009 and it was like rowing a boat at first . . .

    • 0 avatar

      You are right about the viscosity. Many GM vehicles use ATF in their manual transmissions. Honda uses a thin fluid also that can be subsituted for motor oil. The cars that use gear oil all are a bit stiff when really cold, and a new fluid won’t change that much.

  • avatar

    I agree with Ernie on the OEM tires.
    The Original Bridgestone tires on our Toyota Highlander were dangerous POS that wore out quicker than the washer fluid.
    A set of BF Goodrich tires from Costco transformed the vehicle and they are wearing well.
    Car companies put the “cheapest” tire they can “get way with” on their cars.
    The only good (but not great) tires that came with any of my new cars were some GoodYear RSAs on my A4

    • 0 avatar

      My Mazda 6 had Michelin Pilots (V-rated) as the OEM tires.  They were excellent.  However, when the time came to replace them, they were just a bit too pricey, so I put a set of Yokohamas on it (also V-rated).  They’re good, but not quite as good as the original Michelins.

    • 0 avatar

      Tex – the Michelin Energy MXV4 S8 that they now put on the GTi model is, well, an odd performer for a V-rated tire.    The dry traction isn’t that good, but the wet traction is almost as good, which is better than I’d expect out of an OE tire on wet roads.
      My problem with them comes with the cold.  They have very little grip when it gets below 25F and that’s making me nervous.  I think I’m switching them out (keeping the tires if I trade it) with some Yokohama Avid H4S — I liked how both the Avid Touring and Avid TRZ handled in the cold and on wet/dry pavement.
      Convincing the wife to trade out tires on a “brand new” (22k miles since March) vehicle has been an uphill sell.

  • avatar

    My brother has one of these cars, it looks exactly like the one in the pic.  I love driving it and I never refuse to carsit for him when he goes on vacation.

    I know the motor mounts on these case are very weak and don’t hold up at all to the power the motor makes.  From what I’ve read, a lot of the shifting problems can be attributed to a busted lower engine mount. makes a great poly mount for it that doesn’t affect drivability.  This may alleviate a lot of the problems you are having and the part is only $129.  BTW, I don’t work from them and I’m not advertising their product.  I am just going on what I have learned from my brother’s car.

  • avatar

    As long as the fluid meets OE specifications, it should be fine for warranty. (It’s the law, as I recall.)   But, does Synchromesh meet OE specifications? I honestly don’t know.
    Why not use a quality 3rd party fluid that meets the specification?  I run RedLine MT90 in my RX8, RX7 and MazaSpeed Protege.  They meet OEM specifications  for those cars (it’s in your owners manual, the 3 might be different) and are readily available at your local auto-parts store.
    The difference in shift quality on the RX8 and Protege was noticeable. (Hard to tell on the RX7, it’s a track car.)  The shift got noticeably better on the MSP (probably most relevant to your 3) and even “fixed” a 2nd gear synchro grind.
    First fluid change on the RX8, I didn’t have the time/facility to do it, so I just brought my fluid in to the dealership during the regular scheduled maintenance, and got them to use my fluid instead.  No issues.
    I did the next change my self, as well as the change on the MSP.  Took maybe a half hour of  time.  It’s really no harder than changing oil.  The bulk of the time was spent fumbling with the pump to get the fluid up to the file hole.
    Depending on the cost of the fluid, $200 may or may not be fair.  I can’t see it taking more than an ours labour to do the fluid change.
    BTW, a bonus tip (in the Piston Slap way) when changing transmission fluid, ALWAYS pull out the fill plug before you pull the drain plug.  That way you know if you won’t be able to get new fluid in before you drain the old fluid.

    • 0 avatar

      This bears repeating; thumbs-up redshift.

      When changing transmission fluid, ALWAYS pull out the fill plug before you pull the drain plug.  That way you know if you won’t be able to get new fluid in before you drain the old fluid.

    • 0 avatar

      “BTW, a bonus tip (in the Piston Slap way) when changing transmission fluid, ALWAYS pull out the fill plug before you pull the drain plug.  That way you know if you won’t be able to get new fluid in before you drain the old fluid.”

      The most important piece of advise possible when dealing with transmissions and differentials.

  • avatar

    If anon wants a good independent mechanic in Chicago, I highly recommend Power King at ~ 2300 W. Howard on the far north side of the city.  I have been with him for several years.  Ask for Mike (the owner) and he’ll take care of you.  He lets me pick & choose my oil/parts for the STi and will put them in no questions asked.

    Edit: Now that I think about it, Power King is on the north side of the street so they may be listed as being in Evanston, IL.

  • avatar

    It’s not “GM Syncromesh” that’s the magic potion, it’s GM Syncromesh FM. BIG difference.

    The regular stuff is just regular manual transmission oil, the “FM” is friction modified. It’s got a semi-synthetic additive package that makes syncros (which are probably causing your “crunchyness”) sing an Aria.  Gm developed this for their mid-size trucks a few years back, but it seems to work wonders in all kinds of manual gear boxes.
    I’ve personally used it for years in BMW’s and Honda’s, always with better than new results.
    As far as $200 for a tranny oil change- not on anything that isn’t a facking Ferrari. What is that dealership drinking? Must be a good vintage.
    Even full synthetic BMW OEM  transmission oil is about $15.00/qt. Most manuals take about 2 quarts. Do the math for your labor charge. Outrageous for a Mazda. They were just trying to blow you off.
    OP, go find a guy with a clean shop and a lot of cars outside-it isn’t rocket science to change it out.  Two plugs off-drain-replace plugs. Any non-idiot can handle it really.
    IMO if you have a warranty and you want to go non-oem with anything, you better do it quietly, and outside the dealer’s knowledge.
    I offer the following three points in this situation:
    1: I would bet my entire garage that a dealer would not be able to tell the difference between any install lubricants in you car, as long as the application is correct (don’t use ATF in were MTF is called for), and it’s not purple(without mentioning any Royal names).
    2: I’ll be happy to pick you up and drive you around(for a reasonable fee) while your car sits waiting for a court date when the dealer denies your warranty coverage  for non-oem parts or unspecified fluids.
    3: Do not identify yourself, or have your vehicle associated with your desire to change to a non-OEM anything. If  Mazda can deny warranty coverage for “assumption of racing activity due to a SCCA window sticker” then they will take any wiggle room you give them to get out of a warranty claim.
    Yes, you may have that silly MM act on your side, but you will have to prove that you did no harm by using whatever you used.  With in-house legal departments and ‘expert’ factory testimony, you are doomed to a war of attrition.
    Happy shifting.


  • avatar

    The Miata forums have a lot of “GM syncromesh with friction modifiers” users, but even more fans of Redline MT-90 (or MTL, or a mix of both, in colder climates).  I use MT-90 in my ’02 Miata and it made the relatively lousy Aisin 6-speed 90% better.

  • avatar

    Why not 100% Redline MTL.  It worked wonders in my BMW. What IS the Mazda spec fluid, anyway? As I think has been implied, but not necessarily stated clearly in this thread, friction characteristics play at least as much a role in transmission fluid performance as viscosity.  Every manual transmission that the OE specified Dexron/Mercon ATF, due to its universal availability,  shifted better with a different fluid, from Type F ATF to Redline MTL.

  • avatar

    Even though this is a totally different vehicle, the NV-3550 used in the older Jeep Wranglers are known for being stiff and notchy. Many people on the various forums seem to get good results from Amsoil’s manual trans fluid – I’m about to try it myself since I’m due for a change (even though my trans doesn’t feel particularly notchy to me). I’d be surprised if they don’t have a fluid that meets Mazda’s specs. 

  • avatar

    Cammy Corrigan:
    Complete nonsense, you talk to anyone that bought a new car with GoodYear RS/A and ask them how does it feel to slide all over the road when it’s wet or snowy, and on top of that they got the nerve to charge premium for replacement! $210 per tire for Mazda3 hatch (205-50  17), I might say they had good grip on dry, but they went BOLD after 28k miles, and trust me, I driver very gently.

  • avatar

    Cammy Corrigan:
    Complete nonsense, you talk to anyone that bought a new car with GoodYear RS/A and ask them how does it feel to slide all over the road when it’s wet or snowy, and on top of that they got the nerve to charge premium for replacement! $210 per tire for Mazda3 hatch (205-50  17), I might say they had good grip on dry, but they went BOLD after 28k miles, and trust me, I driver very gently.
    Needles to say that I replaced them with other brand, (under the same roof) so much better and cost exactly half, Dunlop SP Sport that came with 60k mile warranty.

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