MT oil change interval


#1

Hi All

My 2013 Mazda 6 does not specify an oil change interval for the manual transmission. I will ask the dealer for their recommendation when I take the car in for a 20,000 mi oil change soon. I wanted to get y’all’s opinion as well.

Thanks


#2

Most vehicles don’t have an oil change interval for their manual transmission.

It really depends on what type of oil is used.

Is it gear oil? If so then 100k mile change should be fine.

Is it ATF? Then I’d change it every 50k miles.


#3

I have an '03 Honda Civic with a manual transmission. My plan was to buy it new and run it for lots of years and miles. I change the transmission fluid about every 50K miles. The car is now at 150K and still going strong. I only use Honda brand manual transmission fluid.

A manual transmission is not subject to combustion by-products and stays pretty clean so you can stretch the change intervals with less damage than not changing engine oil. Some manufacturers don’t recommend changing the manual tranny oil, but I think it is a good idea to get fresh oil in there from time to time. In your case I’d not go beyond 100K miles on the original transmission oil. And I’d use a Mazda brand fluid when you do change it.


#4
The car is now at 150K and still going strong. I only use Honda brand manual transmission fluid.

What type of fluid is recommended for the Honda?


#5

I have seen everything from motor oil to automatic transmission fluid used. Where I last worked, a physics teacher with his doctorate in physics along with th chem teacher who had his masters, both did much of their own maintenance and both swore by using auto trans fluid in their manuals in colder climates. They did year round as well. My previous Hondas of old used motr oil. But, modern transmissions maybe enough different, I would stay exactly with the recommended interval and fluid type. If none is recommended, 100 k would be my starting off point too.


#6
Where I last worked, a physics teacher with his doctorate in physics along with th chem teacher who had his masters, both did much of their own maintenance and both swore by using auto trans fluid in their manuals in colder climates.

My 84 GMC S-15 5-speed manual used Dexron-III ATF.

I wouldn’t use ATF in a manual if it wasn’t recommended by manufacturer.


#7

This car uses synthetic 75W90 and the service interval is realistically none. Replacement of the fluid can be done at the owners discretion but is not required.

We usually only change the fluid if there is some reason to be working in the area such as a clutch job.


#8

"I wouldn’t use AFT in a manual if it wasn’t recommended by the manufacturer. "
Neither have I. But, I was sure temped after talking with these guys, especially the physics teacher. He just said that AFT is an excellent lubricant and flows much more freely in cold weather making shifting much easier. It was some years ago (20) but he kept his Mazda truck for over 150k and never had a problem. After doing a little research too, it was common in some older GM manuals and was recommended by Chrysler and others as a cold weather alternative. If appeared the lube of choice in some manuals due to the synchronizers and obviously causes no harm to the rest. It seems to have excellent lubrication properties and the additives for automatic purpose were inconsequential to a manual. That was pretty much the attitude of those I knew who used it. The co worker said I could just throw it into any manual. I didn’t but this guy was amazing listening to just about anything mechanical.


#9

Mazda trucks have used ATF as MT fluid since the 90’s. I serviced a few back in the day. I had a 1990 Mazda Protege and the manual said to use Dextron III or 75w90. When I got it at 77, 000 miles, it had Dextron III in it.


#10
After doing a little research too, it was common in some older GM manuals and was recommended by Chrysler and others as a cold weather alternative.

Yea…I know…my 84 GMC was DESIGNED to use ATF. Not too sure if it’s acceptable to use ATF in a tranny that was designed to use Gear Oil.


#11

From my reading, GM needed it to lube the composite synchronizers they used. It had the best properties to do the job. It was required for it but still worked on all the other parts and non composite synchronizers as well. Me ? I’m not sold either but I have to say, he was very convincing, mainly because of his reputation. We would talk for a time after school often though after a few minutes, I just pretended to listen as he usually got way over my head.


#12

If there isn’t a recommendation in the owner’s manual and the car is driven in a more or less normal manner – not like a taxi cab or a Bonneville speed racer — I’d probably just change the transmission oil each time the clutch needs replacement. You should however check the transmission oil level occasionally. I check it on my Corolla once a year.


#13
You should however check the transmission oil level occasionally. I check it on my Corolla once a year.

That’s not very easy on a manual tranny.


#14

Not easy to check the manual tranny fluid level? Just a DIY’er and only checked it on a late 70’s VW Rabbit and early 90’s Corolla. New cars or non-econoboxes could well be different. But on both of my cars it was(is) pretty easy. Not as easy as checking the oil. If you mean it is not something the normal car owner would undertake themselves, that’s probably true. But a mechanic could check the manual transmission level in both of those cars in less than 10 minutes. But you have a good point @MikeInNH , I should have said “ask your mechanic to check the level” rather than “you should check the level”.


#15

The last manual Tranny I owned was on my 98 Pathfinder. The only way to check the level was to remove the filler bolt and stick a finger in there to see if you feel any oil. If you can’t then you need to add some. To that meant putting the vehicle on a lift or if at home - putting all 4 corners on stands and crawling under to remove the bolt. The vehicle needs to be level when doing this or you won’t get an accurate reading. Ever try leveling a car on 4 stands?


#16

i changed the MT oil in my Mazda3, at 60k miles, when I changed the oil, used synthetic gl4 tranny oil, and switched to synthetic for the engine, changed the PS fluid at the same time, synthetic for that also. much nicer in NE winters…


#17

@MikeInNH - the '03 Honda owner’s manual states you can use 10W-30 motor oil in the manual transmission as a temporary measure. Once you can get Honda manual transmission fluid the 10W-30 fluid should be changed in favor of the Honda brand fluid.

When I have the tranny fluid changed in my Civic I buy the Honda brand oil from a Honda dealer and have my mechanic use it.


#18

You can not substitute ATF (0W-20) for the manufacturer’s recommended 75W90.


#19

Of the four MT cars I’ve owned, two called for ATF, one gear oil…and I can’t remember what the Contuor used.

Rattlegas, gear oil is “weighed” using a different test and 75w90 is closer to 15w40 diesel oil (in viscosity) than anything.


#20

MTB … yes, I can see how checking the manual xmission fluid would be difficult for a DIY’er if you had to jack up the car first. And keep it level at the same time. On the two cars I mentioned, the access to the fill-plug is such that you can check the level without jacking up the car, on level ground.