2016 Mazda6 6MT Gear Oil Change

[Cruisin'n5thgear]

Recently changed out my Mazda6 MT gear oil from stock to Redline 75W80 API GL-4. Original oil was still performing fine, but with a hint of notchiness.

Old fluid drained out fine, slightly brownish color but no particulates that I could tell. Used this tutorial: https://www.mazda6club.com/threads/diy-manual-gearbox-fluid-change.432914/

Slightly better shifting! Notchiness is pretty much gone, and the synchros seem to be working slightly better - a hundred plus miles since the fluid change.

At 140k miles, I figured it was about time. I normally go with Mazda OEM fluids or parts for this type of thing, but very happy with Redline in this use case.

 

[Cdn17Sport6MT]

It's undeniable that Redline MTL will make the shifts smoother and the "grouchiness" of the 'box less when cold. No one in this Forum or on Mazda3Revolution, or on Mazda6club, nearest as I can tell, has experienced heightened wear issues with the Redline either.

I'm a Luddite... I'll still stick with the OEM fluid... but I may yet end up being convinced otherwise.

 

[Cruisin'n5thgear]

I've used the Mazda 0w20 as long as I could find an affordable source ... they do make a good transmission and quality fluids, for sure. Universally the Redline seemed to be the favored alternative so I went with it.

Back when I had the 2000 Miata, it was either Redline or Motorcraft that was the fluid of choice.

 

[Cruisin'n5thgear]

It's undeniable that Redline MTL will make the shifts smoother and the "grouchiness" of the 'box less when cold. No one in this Forum or on Mazda3Revolution, or on Mazda6club, nearest as I can tell, has experienced heightened wear issues with the Redline either.

I'm a Luddite... I'll still stick with the OEM fluid... but I may yet end up being convinced otherwise.

How often do you change your 6mt fluid? I see you have a Mazda6 as well - what a great vehicle.

 

[Cdn17Sport6MT]

How often do you change your 6mt fluid? I see you have a Mazda6 as well - what a great vehicle.

I have very low miles on my 17, so I have not changed the factory fill transaxle lubricant.

Re your comment on the car... I partially agree... The 3rd gen Mazda6 is a reliable, long-lived vehicle if taken care of... and the drive quality is pretty good. However, Mazda's are built to a budget... and I would comment that:
- sheet metal is very, very thin, leading to poor durability;
- transaxle (6 speed manual) is "half the transaxle" my Camry 5mt is (an S51 Aisin)... in that speed-gear dog rings (and synchro sleeves) are fine-toothed and shallow axial engagement... and speed-gears do not turn on half-shell caged needle bearings.... It 'kinda feels "sproingy" if that's a word?;
- paint is very susceptible to rock chips;
- car has interior noise that ought to have been properly mitigated;
- 2.5 litre 4 cyl has "weakness" in the lower rpm ranges... comes into its own above 2800 rpm... decent mid range... coarse, up-top;
- actual build quality, gaps, finish is decent;
- subframes, suspension members - almost all being steel pressings, welded fabrications, are so poorly paint-prepped and painted, that it amazes me: they have a strong propensity to corrode;
- carpets are hardly better than cardboard (pile thickness is laughable);
- cloth seats are only so-so by way of fabric quality; and
- electric power steering is pretty good as those systems go... but I can tell it's not a (superior, in my view) HPS system.

I paid low $ for the car and I got a lot of car for the $... but I'm struck with how cars of late have been so, so cheapened by way of materials quality, "stoutness", durability.

 

[Cruisin'n5thgear]

I have very low miles on my 17, so I have not changed the factory fill transaxle lubricant.

Re your comment on the car... I partially agree... The 3rd gen Mazda6 is a reliable, long-lived vehicle if taken care of... and the drive quality is pretty good. However, Mazda's are built to a budget... and I would comment that:
- sheet metal is very, very thin, leading to poor durability;
- transaxle (6 speed manual) is "half the transaxle" my Camry 5mt is (an S51 Aisin)... in that speed-gear dog rings (and synchro sleeves) are fine-toothed and shallow axial engagement... and speed-gears do not turn on half-shell caged needle bearings.... It 'kinda feels "sproingy" if that's a word?;
- paint is very susceptible to rock chips;
- car has interior noise that ought to have been properly mitigated;
- 2.5 litre 4 cyl has "weakness" in the lower rpm ranges... comes into its own above 2800 rpm... decent mid range... coarse, up-top;
- actual build quality, gaps, finish is decent;
- subframes, suspension members - almost all being steel pressings, welded fabrications, are so poorly paint-prepped and painted, that it amazes me: they have a strong propensity to corrode;
- carpets are hardly better than cardboard (pile thickness is laughable);
- cloth seats are only so-so by way of fabric quality; and
- electric power steering is pretty good as those systems go... but I can tell it's not a (superior, in my view) HPS system.

I paid low $ for the car and I got a lot of car for the $... but I'm struck with how cars of late have been so, so cheapened by way of materials quality, "stoutness", durability.

I'd pretty much agree with everything you said. We got ours for 19k out the door back in '16, so a lot of car for the money. Yes, the sheet metal is incredibly thin - aircraft-thin, I'd say. The transmission has an imperfect feel (compared to my Miata, gold standard for shifting). Rock chips ... yes. Noise that is a bit too high, the '16 has a particular wind noise coming from the driver door. Later years had that fixed.

As far as the rest of the interior, in agreement - although for the money, it is very acceptable for a DD. Makes our Yukon SLT look like a luxury vehicle in comparison. But we were happy with the Mazda6 for years with kiddos 0 through 2. #3 on the way made us upgrade to the Yukon, and I'll likely use the Mazda6 for my work vehicle.

Shortcomings aside, it has great driver dynamics, and I can't argue with a quasi-full size vehicle that returns above 30 MPG in all modes of driving, to include 80 mph interstate cruising.

Compared to a Jeep Wrangler Unlimited, it handles like a dream for long road trips

 

[Pew]

I've used that in the Evo as the "redline cocktail" involving two bottles of MTL and 1 bottle of MT90 along side the OEM Diaqueen fluid and Amsoil 75w-90. I couldn't notice a difference between them other than having fresh fluid; not that it was bad or anything but the Evo forums hyped it up as the holy grail of trans fluid. I would have tried Motul on the fourth and final change but the prices were crazy high.

 

[ArrestMeRedZ]

Also 2017 Sport M6, I figured I'd just use the Amsoil manual transmission lube I had on hand, but lo and behold the Amsoil site has no recommendation for that application. Looks like I need to buy a couple of quarts of the Red Line.

I took the car into the dealer last year (the first time) for an oil change because I got lazy and didn't want to rotate the tires myself. At 15k miles, magically the air and cabin filter needed changing, the 10 year coolant needed flushing at the 5 year point, and get this, in bone dry Las Vegas, the brake fluid needed flushing too. Of course, I asked what type of test they ran on the brake fluid to determine it needed changing. No answer.

 

[Cdn17Sport6MT]

Of course they didn't test the brake fluid (almost for sure)... But having said that in my estimation brake fluid flushes (including clutch hydraulics circuit) are good business at two year intervals. Doing that, you may NEVER, over the life of the car, 'hafta replace any hydraulic cpts, let alone the $$$ abs unit. Other filters... is it dusty in AZ, well, particularly for the places you go to?

 

[ArrestMeRedZ]

I do have a break fluid tester, but don't need to use it that much. It is so dry here in Las Vegas I've done overkill on the fluid on my other vehicles, changing it out only when I replace the pads and rotors. In 2 years the only water the car may see is at the car wash. It is dusty here so I do replace filters at the 20-30k mile point. They have never been that bad. I am very retentive about making sure intake systems are sealed.

But the point is the business model of dealers and repair shops in this town is not to let you out without spending at least $600. Whether maintenance is required or not.