Are there drawbacks to aftermarket manual transmission fluid?

[EPSi2FKR]

What are the downsides to changing MTF to something aftermarket? … i.e. MOTUL gear 300, Amsoil synchromesh, etc.

So, after 5 track weekends last year and 10,000 miles I’m making the decision to change the transmission oil. We are sending it off for analysis to see when is the right time to change the fluid for me. I’m switching to MOTUL gear 300 (mainly because the shop I use is a MOTUL dealer). The lead tech asked me, “Are you sure you want to change from OEM? The shifting may be a bit worse when cold but nothing too bad.” Thoughts?

Sponsored

 

[.grimace]

I’ve had redline and amsoil transmission fluid. Both were better than OEM even in cold weather. Tech is full of it

 

[EPSi2FKR]

I’ve had redline and amsoil transmission fluid. Both were better than OEM even in cold weather. Tech is full of it

Oh, he wasn’t being rude at all. It’s a speed shop. Just being cautious, thorough and helping me make an informed decision. Shoot, I even got like “good doctor” vibes from the guy!

 

[Vincent@27WON]

We have had no issues getting away from the OEM fluid on our FK8. We have Torco in it now and it works great.

 

[.grimace]

Oh, he wasn’t being rude at all. It’s a speed shop. Just being cautious, thorough and helping me make an informed decision. Shoot, I even got like “good doctor” vibes from the guy!

ahhh. He might just be one of those guys who gives out advice he has no idea what he’s talking about then. Don’t trust someone just because it’s a “speed shop” tons of shit work out there.

 

[JO3L]

Just switched out the OEM fluid to Motul 300 at 28k miles and notchiness in the shifter I was experiencing is completely gone. Since it is thicker oil than OEM the only concern I would have would be if I lived in an extremely cold environment.

 

[san44]

ahhh. He might just be one of those guys who gives out advice he has no idea what he’s talking about then. Don’t trust someone just because it’s a “speed shop” tons of shit work out there.

In fairness, the Honda OEM MTF is of a lower viscosity weight. I believe it is 75w-80? Motul Gear 300 is 75w-90. Cold weather performance could technically be affected. Now, can the average Joe notice this? Who knows. Maybe dependent on their weather or experience.

 

[ez12a]

In fairness, the Honda OEM MTF is of a lower viscosity weight. I believe it is 75w-80? Motul Gear 300 is 75w-90. Cold weather performance could technically be affected. Now, can the average Joe notice this? Who knows. Maybe dependent on their weather or experience.

Inferring from the 2021 owner's manual Honda MT is closer to a 0w-20 or a 5w-20. Those weight motor oils can be used a as temporary measure in a Honda MT.

 

[.grimace]

In fairness, the Honda OEM MTF is of a lower viscosity weight. I believe it is 75w-80? Motul Gear 300 is 75w-90. Cold weather performance could technically be affected. Now, can the average Joe notice this? Who knows. Maybe dependent on their weather or experience.

Yea I don’t think anyone would ever notice. I drive my car at or under freezing temps and don’t notice anything. Parked in a garage though.

 

[san44]

Inferring from the 2021 owner's manual Honda MT is closer to a 0w-20 or a 5w-20. Those weight motor oils can be used a as temporary measure in a Honda MT.

Actually, they are the same. Honda MTF is still 75w-80 in gear oil which is equivalent to 20 or 30 weight engine oil. They are the same viscosity. Gear/transmission oil is measured differently from engine oil. The difference is in the additives.

 

[ez12a]

Correct me if I’m wrong, but motor oil is measured/labeled differently than gear oil. Therefore Honda MTF can be


Actually, they are the same. Honda MTF is still 75w-80 in gear oil which is equivalent to 20 or 30 weight engine oil. They are the same viscosity. Gear/transmission oil is measured differently from engine oil. The difference is in the additives.

TIL, thanks!

 

[ValkenDnB]

We have had no issues getting away from the OEM fluid on our FK8. We have Torco in it now and it works great.

I second torco. Running their MTF and 5w-20 engine oil on my stock civic si and the shifter slides in to gears like butter.

 

[jlamb30]

I second torco. Running their MTF and 5w-20 engine oil on my stock civic si and the shifter slides in to gears like butter.

Is your shifter setup still stock, too? I have the 20+ FK8 shifter plus Acuity bits.

 

[ValkenDnB]

Is your shifter setup still stock, too? I have the 20+ FK8 shifter plus Acuity bits.

Yep stock shifter for now. Have the 2020 type r shifter waiting to be installed still along with some other goodies.

 

[jlamb30]

Yep stock shifter for now. Have the 2020 type r shifter waiting to be installed still along with some other goodies.

You'll LOVE it!!!!! The difference is amazing without forking over the cash for the fully adjustable Acuity shifter.

Sponsored