6MT Transmission Fluid Flush/drain&fill Questions

So I have a new-to-me 2019 6MT with 42k miles- poked around a few threads on swapping the tranny fluid as I'm sure it hasn't been done yet and have a few questions

I've heard mixed reviews on using Redline MT90 - wondering what oil ya'll recommend, I live in Denver so curious if altitude or weather would lean a suggestion one way or another

Do I need to do an entire flush of the system when swapping fluid brands? or will a traditional drain&fill work?

Thanks

 

I recommend MT-90. Night and day difference in the smoothness of this transmission. When it was new, it was knucklier than a skeleton's hand. Now it's smooth, and it slides into 1st if I double clutch. I live in Virginia pretty much at sea level, not sure how Colorado would affect it, if at all.

Check out this maintenance guide. You absolutely need to torque both bolts to spec because they're so short-threaded. No need for a flush, drain and fill should do the job.

https://www.tacomaworld.com/threads/3rd-gen-diy-maintenance-quick-reference.406712/

 

What @bonifacio_629 said. MT-90 has been my go to for a couple decades now. It will also help if you find 1st gear blocking you at a stop.

Completely worth it.

 

MT90 will work fine, even in Denver. I had no issues at all this past winter when we had the below zero cold snaps.
I've been using it in all of my manual transmissions.

A simple drain and fill will work.

Regardless of what anyone says, you're unlikely to notice a major difference between fluids. Redline, Royal Purple, Amsoil, yada yada yada...
Pick one with the correct specs, and you'll be fine.

 

Congratulations on the 3 pedal job

I replaced my factory fill (no issues) at around 30k with Motorcraft Synthetic (XT-M5-QS). It was an immediate and noticeable improvement, the shifting was slicker for lack of a better word. Still not a sports car naturally but it was an improvement just the same.

The Motorcraft fluid meets the Toyota specifications, it is the recommended viscosity (SAE 75W-90) and carries the correct GL-4 rating (this is important).

Rock Auto had the best price.

https://www.motorcraft.com/us/en_us...ull-synthetic-manual-transmission-fluids.html

No flushing required, just a drain & fill.

 

I went with Amsol MT 75W90 GL4...and I'm not an Amsol guy. Only reason I didn't get the Redline was because there was a delay in availability. GL4 and you're golden.

 

Redline MT-90 is very popular, even across all brands of manual trans vehicles. It flows to about -70F so you'll be fine.