FL5 Transmission Fluid recommendation

[Unobtanium]

More like Honda's been using the same fluids and transmissions for decades and they just do what's best for their packaging. Nothing wrong with the fluid choice

You're telling me that a company that molds mm thick canards onto a front air dam flap just put whatever was handy in the gearbox?

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[Cueyo]

You're telling me that a company that molds mm thick canards onto a front air dam flap just put whatever was handy in the gearbox?

I mean they've used the same transmission for the type R for over ten years, just with upgrades to different parts. It's not like Honda didn't develop(?)/choose the mtf to not handle the max case. It's definitely not just what was handy, it was made with a bunch of Honda manual transmissions in mind. Again, packaging to save money on development for the whole brand.

 

[Spart]

You're telling me that a company that molds mm thick canards onto a front air dam flap just put whatever was handy in the gearbox?

Pretty much.

If you think otherwise, you're both over-thinking and under-thinking the whole situation:

• Overthinking: Honda's MTF isn't all that special, and it doesn't need to be. Honda also doesn't use a special engine oil for these cars, or a special engine oil filter. Hell, they don't even use DOT4 brake fluid - they use DOT3 like it's 1999. The consumables are designed with the dealership's service department in mind.
• Underthinking: the qualities of a MTF that might make an owner choose one over the other are only somewhat related to the qualities of a MTF that might make Honda choose one over the other.

 

[Unobtanium]

I think also it would help to keep in mind its not just a transmission. It'd also a torsen style diff that is going to be seeing whatever fluid you choose. I feel like Honda oem changed often enough is a good move.

 

[Spart]

I think also it would help to keep in mind its not just a transmission. It'd also a torsen style diff that is going to be seeing whatever fluid you choose. I feel like Honda oem changed often enough is a good move.

It's worth bearing in mind insomuch as it doesn't matter at all, and that's straight from the manufacturers of such devices.

There are other types of LSDs that require specific lubricant additives to function properly, and ours isn't one of them.

You would do well to read my thread on manual transmission fluid disinfo, particularly this post, before you start spreading more disinfo.

 

[Unobtanium]

Pretty much.

If you think otherwise, you're both over-thinking and under-thinking the whole situation:

• Overthinking: Honda's MTF isn't all that special, and it doesn't need to be. Honda also doesn't use a special engine oil for these cars, or a special engine oil filter. Hell, they don't even use DOT4 brake fluid - they use DOT3 like it's 1999. The consumables are designed with the dealership's service department in mind.
• Underthinking: the qualities of a MTF that might make an owner choose one over the other are only somewhat related to the qualities of a MTF that might make Honda choose one over the other.

FL5 CTR factory spec is DOT4 brake fluid.

 

[Spart]

FL5 CTR factory spec is DOT4 brake fluid.

No, it isn't.

 

[Cueyo]

I think also it would help to keep in mind its not just a transmission. It'd also a torsen style diff that is going to be seeing whatever fluid you choose. I feel like Honda oem changed often enough is a good move.

Also doesn't have a torsen diff, it's a helical lsd that's mechanical

 

[johnloov]

Other than DOT 4 Castrol SRF Fluid - required for racing

What ever you choose, engine oil, or transmission fluid - OEM or not OEM, change it frequently - flushing out contaminants - engine oil every 2-3000 miles( 2-3 track days ) - and transmission fluid every 5,000 miles - will help much more than a specific type of fluid used in a longer duration.

 

[Spart]

Other than DOT 4 Castrol SRF Fluid - required for racing

What ever you choose, engine oil, or transmission fluid - OEM or not OEM, change it frequently - flushing out contaminants - engine oil every 2-3000 miles( 2-3 track days ) - and transmission fluid every 5,000 miles - will help much more than a specific type of fluid used in a longer duration.

Transmission fluid every 5000 miles is straight-up insane advice unless you're doing something that gets the fluid very hot regularly.

Taper your change interval off as you stack miles on. The wear starts out high and will taper off and that's the only real source of contaminants in MTF.

MTF is not exposed to combustion byproducts like the engine oil is, it can last a very long time as long as you aren't cooking it.

 

[johnloov]

Transmission fluid every 5000 miles is straight-up insane advice unless you're doing something that gets the fluid very hot regularly.

Taper your change interval off as you stack miles on. The wear starts out high and will taper off and that's the only real source of contaminants in MTF.

MTF is not exposed to combustion byproducts like the engine oil is, it can last a very long time as long as you aren't cooking it.

I only follow the data, and everyone should also. Most always, it's best to flush out break in metals as those circulate in the transmission and engine oils for the first 10,000 miles. Scientifically proven.

These Blackstone reports also proved my transmission fluid was not cooked. It's just the reality of breaking in metal on metal.

As you can see in the lab reports.

I changed my Transmission fluid at 3,800 miles and again at 6,642 miles. When I recommended 5000 miles, I was being conservative.

I'll have another analysis soon on at 13,000 miles.

If you want to follow data driven science on actual lab results, non-emotional - reality. We are posting these on this these thread.

https://www.civicxi.com/forum/threa...ype-r-k20c1-engine-oil-analysis.57366/page-23

Adjust your transmission change intervals and engine oil intervals based on your lab data.

It is true, some oils help ensure longer change intervals, and it is true how you use the machine, and exponentially more so during initial break in, more service intervals help ensure longer longevity.

Listen to data -

Hope that helps.

 

[Spart]

Scientifically proven.

As you can see in the lab reports.

Oh cut the BS.

Nobody needs to change their MTF every 5000 miles perpetually, and you do not have data that supports that because you've barely done 10,000 miles in the car.

You need to put the ChatGPT down, it's gassing you up when you decide to be extra for no reason.

And Jon... the guy who DOES have the data doesn't make that argument either.

 

[J35W2]

I changed my oil at 750 miles & then again at 2,500 to remove all the break in bits. Going to change again at 5k. If cost is your main concern then do what the manual says. If you don’t mind the cost, change it early the first 3 changes. The Honda synthetic is good, just change it every 3k after getting the break in bits out. If you want the best engine life, change it early. I’m changing the tranny fluid to Amsoil Synchromesg this week at 4k miles. Everyone has an opinion on the best tranny fluid, but I’ve used Amsoil on ALL manual Hondas & will swear by it.
Just depends on if cost or engine life matters more. Just my humble opinion.
My fk8 would grind on the 1-2 shift on heavy throttle. Amsoil helped, but never changed the RMM. Put in the Cobb rmm last week & will recommend it all day. With Amsoil Synchromesh, I expect the best. Watch the oil dude on YT about oil & trann fluid. Dude is a wealth of data based knowledge with impeccable experience.

 

[Spart]

I changed my oil at 750 miles & then again at 2,500 to remove all the break in bits. Going to change again at 5k. If cost is your main concern then do what the manual says. If you don’t mind the cost, change it early the first 3 changes.

I actually agree with this logic, but if you aren't getting the trans fluid extremely hot you should taper off to more normal 20-60k intervals once initial break-in is complete.

The overwhelming majority of your break-in is happening in that first few thousand miles. I changed my trans fluid out at 3,920. Lake Speed Jr. recommends 5000 miles for the first change. See the video I posted above.

By Honda's standards this is overkill. I'm not sure if anyone knows whether there's a fixed mileage at which the Honda Maintenance Minder will give you code 3 indicating that it's time to change the transmission fluid, however the UK owner's manual explicitly calls out 75,000 miles for normal use. It also says you should change it early every 37,500 miles if the car is subjected to "severe conditions" as follows:

I think something like 5k-20k-50k-90k-130k-170-210k would be great for the majority of folks. That's 5k, 15k, 30k, 40k, 40k, 40k, 40k.

If you are a track rat (particularly on hot days) I would pay close attention to how the synchros feel. You'll feel when it's time as much as anything.

If you aren't doing anything to severely cook the fluid, changing too often is just a waste of time - unless you need a reason to get away from your wife or something.

 

[J35W2]

Totally agree. Oil & Tran fluid is the blood of your R. Don’t over do it, but early is better especially depending on how hard you drive especially if you track it. Keep those metal on metal bits lubricated with clean fluid & keep the synchros happy if you plan to keep your R running tits for a long time. Proper maintenance is the jam for long, optimally performing motor & trans.

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