I just bought a 2012 Mazdaspeed 3. The gearbox (6-speed manual) shifts very nicely, but it makes some gear noise below 20 mph in 1st and 2nd gear.

I was thinking about swapping out the factory lube for something better. Any recommendations on the brand? I'll obviously be using whatever weight is called for by the manufacturer.

Also, my apologies if this is repeating a forum/question posted elsewhere.

The safest thing to do, while under warranty, is to stick with the OEM fluid. However, if you are willing to take on the responsibility of hasseling with the dealer IF something was to happen to the transmission, in regards to proving that the non-OEM fluid DID NOT cause the issue, I'd look into AMSOIL. Simply find the spec' for your car and correlate that to the MTF offered by AMSOIL.

Honestly, I'd stick with the OEM until the warrantey expires, however, I do understand that this is your desire.

It needs a 75w80 GL-4. That's a rather unusual fluid.

Redline has a 70w80 and 75w85. If you're willing to look past warranty requirements, I'd even consider a high-end 75w90 like Motul Gear 300.

if this car is brand new and there is a problem bring it back for service.
do not try to make it better than new because when something happens the stealer will try to blame you!

Really i would NOT mess with it.. See if the others make the same noise go to another stealer and test drive a couple of more of them (pretend to want to buy one otherwise you probably won't get to test drive one) dont listen to the people in service they almost always say its good when under warranty but it almost always needs repair when the warranty expires.

Look into MotorCraft XT-M5-QS ..... Lots of Mazda folks swear by it.

Gear noise in low gears is completely normal. You should come for a ride in my STI some time. You'll forget all about your little "problem" right quick.

With that being said, I changed out my gear oil at around 33k miles. Some said to do so earlier, but I didn't see any need to. I only changed it out for Motul Gear 300 to help with low-temp shifting. It did help some, and I guess the peace of mind of getting the old stuff out is worth something, also.

If you use what's called out in the manual, then there is no need to worry about your warranty. To say you'll have issues with your warranty while using an approved gear oil is foolish. If what was posted earlier is true and the only option, then you may have more trouble than I did with common GL-5 75W-90 gear oil required by Subaru for my application. If there is any provision for using this weight of gear oil I would. Motul Gear 300 is GL-4/GL-5.

+1 forget about fluid making a big diff and youll prob make things worse. What you have there is a high capacity gear design and its attendant racket. A badge of honour. Consider it a rock crusher. Do nothing except enjoy the ride.

Some owner's manuals actually state that at low speeds the transmission might be noisy. In my Audi, for example, it's common knowledge that at low speed when the steering wheel is at full-lock you'll get some clunking from the differentials.

+347890

I've had it in mine for almost 3 years and it keeps getting better BION.

On cold starts, my tranny sounds like it's tumbling marbles about. I do not exaggerate when I tell you it's loud. Before Subaru came out with the following TSB, I had my car in the shop three times that first winter wondering what the heck the problem was. I knew how loud the gears would be, and the STI's propensity for noise-making, but this sounded awful!

Mine is super loud and has been for years. Even rode in a 2011 Saturday adn it was loud too. 15K on the 2011. Mine has 110K. Throwout

Normal for Speeds

I personally swear by Redline drivetrain lubricants, for everything from mild street use to ~500bhp S/C'd track use. It has never failed me, and it is absolutely worth the cost.

I use their D4 ATF in my 328Ci's 6spd Manual (swapped from 06 330Ci ZHP) and used it in the factory 5spd manual before that. In the original trans, there was a noticeable drop in temperature as measured by an infrared heat thermometer (6 locations compared), ranging from about 5-20*F. These were readings taken from the housing, not the fluid itself, but both were done on 80*f days immediately after a 45min (28mi) drive that was exactly the same route both times (2mi backroads, 10mi highway, 8mi backroads, 2mi hwy, 6mi backroads; this is the same exact route I use whenever I am testing something new out as the hwy gets engine oil temps to Op Temp, and all of the backroads are extremely twisty, like insanely so, and this combined with no one else ever being on them amounts to a good testing route...).
That had me very impressed, especially considering that it is similar to what an average trans cooler will give.

I also used their 75w90 Gear Oil in the differential up until I had an LSD made and installed (now I only use the fluid I get from Quaife as doing so warranties a rather pricey hunk of metal!). Same thing happened, I noticed a drop of 5-10*F via infrared thermometer. After installing a Rogue Engineering Aliminum Finned Differential Cover, the total temp drop was 22-28*F, very impressive IMO.

In my 325i, which has its original 5spd manual and non-LS diff, these fluids have been very beneficial. The car is my daily driver (150,135mi), and I keep meticulous records of it as with all of my cars.
When I switched the driveline fluids to Redline ATF and Gear Oil, with the only other change being a fresh batch of RP 5w30 + K&N Oil Filter ("old" oil had 3892mi on it), my average fuel economy went from 27.385mpg to 28.675mpg as measured via both my own calculation and the onboard computer (I always use the same pump at the same Shell as it has 93oct pure gas, no EToH). Weather was similar, and there were no other differences... Fluid that was replaced was OEM BMW fluid from dealership that had 38,228mi on it when dumped.

Other benefits have been: smoother shifting (both w stock shifter in 325 and UUC Evo3 Short Shift Kit + UUC Dual Sheer Selecting Rod + UUC "Race" Tranny Mounts), better economy, less difference in shifting due to temp, lower trans and diff operating temps, and Peace of Mind!

Everyone has different views, and its possible I could have had similar results with a different brand of fluid. I am just providing anecdotes, so don't assume you will have the same experience as me, although almost all of my friends now use RL fluids (in everything from Mini Cooper S, 350Z, S2000, Audi A4 1.8T, Audi S6, BMW 330i, Mercedes C32 AMG, and more) and all have found it to be excellent.

FYI.....
http://www.mazda3forums.com/index.php?topic=153736.0

I was primarily concerned with the tranny noise in 1st and 2nd, that's all. Shifting is not a problem at all. 1st might be a little sticky, but that's usually if you try to engage that gear while moving over 5mph in any MT car.

I had an 07 MS3 GT for a year and noticed it too, though I tend to ignore weird noises in performance cars.