DIY - Transmission / Diff Fluid Change Reference Guide

[Somerandom18]

Originally Posted by arxm

so as per my understanding as I've never done this before on any car is that i need 2.2L of motul 300 75w-90 for the transmission, and can I use the same stuff for the diff?

You can use the same gear oil in the differential in this car.

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[kch]

Originally Posted by arxm

so as per my understanding as I've never done this before on any car is that i need 2.2L of motul 300 75w-90 for the transmission, and can I use the same stuff for the diff?

Correct; you can just get 4 liters of the same fluid.

[Calvin27]

Originally Posted by fl4t

I am feeling the exact same way with Motul 300. It feels the same if not a bit notchier particularly downshifting into 5th at highway speeds.

It's wierd, but after a week and a really hard session in the 'canyons' we call it (touge hehe) gearbox feels the same as before now. Not hard to shift in, but a little notchy. It appears the car needs a lot of rpm to shift well. Diff next.

[arxm]

awesome thank you, i don't know how to use the thanks button bc i can't find it lol but I'm gonna get this fluid changed pronto since thats the case

[Mchilese]

Thanks for that write-up! I did my tranny and diff oil changes along with my engine oil change yesterday. It was the first time I've done a tranny/diff service. I was shocked at how much debris came off on those drain plugs! I bought my BRZ used with 13k on the clock. I've taken it to 20k ,but I thought the fluids would have been changed before I took delivery of the car. I guess not! Glad I did it myself.

Though, I think I'll try those tricks of using a funnel and a hose to fill them, next time. I used a fluid transfer pump, and it was a flippin mess.

Thanks again!

[Exrald]

Idk if it's just mine. After I replaced my Tranny Fluid with Motul, there are times when my shifter has a hard time going in gear. It has happened before, but it has been more apparent on a certain time of the day.

I work 9-5. In the mornings, shifting has no problem. but after work, it's a little bit harder to go in gear. I do warm up my car about 3-5 minutes, but there is still that difficulty. there is also that crunchy feeling while shifting. Is it the shifter? it couldn't be the tranny right?

[Exrald]

Originally Posted by Calvin27

Has anyone done the MT fluid change and noticed it got worse? Does it need to 'run in'? I went for motul fluid as per most of the suggestions here and it actually feels more clunky than what I originally had in there. (I presume it was oem because there were a lot of metal shavings). I drove the car for about 5km changing gears slowly and it improved a bit but the feel is still very notchy compared to previous. freaking out I did something wrong - I made sure i filled it the correct amount, no sure what else could have gone wrong.

I am feeling the same with mine... But it's not always, usually when i get off after work at 5pm...

[Bodalenko]

So having read the last several posts stating that their gear changes were 'notchy' and not as clean and precise as pre oil change, what is the point of changing to Motul?
Also;If the standard motul 300 is fine for gearbox and diff, is the 'LS' version ok to use in the gearbox as well as the diff?
As someone whose gearbox still has a silky change whether warm or cold after 18k miles, I'm reluctant to change to any oil that's going to give me sub OEM performance.

[Exrald]

Originally Posted by Bodalenko

So having read the last several of post stating that their gear changes were 'notchy' and not as clean and precise as pre oil change, what is the point of changing to Motul?
Also;If the standard motul 300 is fine for gearbox and diff, is the 'LS' version ok to use in the gearbox as well as the diff?
As someone whose gearbox still has a silky change whether warm or cold after 18k miles, I'm reluctant to change to any oil that's going to give me sub OEM performance.

It's because the oil had to warm up a bit. After 2-3 minutes, it gets pretty smooth. Once fully warmed up, it's hella smooth. It's worth it!

2013 SCION FRS (Argento)
Instagram: @theunforgottenfrs

[2point0]

Originally Posted by Bodalenko

Also;If the standard motul 300 is fine for gearbox and diff, is the 'LS' version ok to use in the gearbox as well as the diff?

I can't say for certain that the LS oil will be BAD for the trans, but it's more expensive and there's no point in wasting it there. If you're uncertain, just use the regular Gear300 for both trans and diff. You can get away with one less bottle that way.

Or, if you're happy with the current feel, just go by the dealer and get more of the OEM fluid. Probably lots cheaper than Motul. The fancy stuff isn't going to change your life or anything.

[reeves]

Just changed my tranny fluid (Pentosin MTF2) last week, it was putrid black. Wiped it on a clean white bounty towel just to check for a hint of a yellow/brown color. Not a single drop of any shade of brown! I think the towel even wanted to puke.

The differential fluid (Motul 300), however was still a medium maple syrup color.

60K-mile interval seems OK for the differential. I won't be going 60K miles again before changing my tranny fluid.

[strat61caster]

Originally Posted by Bodalenko

As someone whose gearbox still has a silky change whether warm or cold after 18k miles, I'm reluctant to change to any oil that's going to give me sub OEM performance.

Then stick with OE fluid if you're happy with it, if it ain't broke, don't fix it.

People switching to Motul are typically not the happiest with the OE fluid, I did my change at 30k miles, but Motul wasn't some magic fix so I'll be trying a different fluid coming up on 60k miles this summer.

[KiP40]

So I just changed the transmission and differential fluid with Motul.
Just a few thoughts:

- don't be incompetent like me and utilize the two new crush washer for both the tranny fill and drain plug and completely forget to use the second on the differential drain plug smh. (I resorted to flipping the differential gasket and re using it praying it doesn't leak).

- due to the awkward placement even with Motul hose I was only able to add about 1.2 L to the differential. I did the pinky test, weeping test, and car was leveled. Based on previous comments hopefully this is fine.

- took it for a quick drive in the AZ heat and immediately felt a much smoother shift and downshift to second gear. Overall it felt like a much more refined transmission.

Lastly, has anyone had any problems re using the washer? Is it something I should check weekly for any leaks?

[reeves]

Originally Posted by KiP40

Lastly, has anyone had any problems re using the washer? Is it something I should check weekly for any leaks?

Yes, I ran into an unexpected problem when I re-used my washer.

No, it didn't leak (the bottom of my transmission is completely dry). But the washer got crushed/squished to the point where I couldn't take it off drain plug anymore. Basically, the inside diameter of the washer became smaller than the diameter of the threads on the drain plug. The outside diameter of the washer expanded out, while the inside diameter expanded inward from being crushed too much. Hope this makes sense.

Not a big deal, but I went ahead and ordered a new drain plug for next time. I had to put the old drain plug back on (along with the previously twice-crushed washer) since it was gonna take a few days for the new drain plug to arrive. I've checked it a few times after driving around for a few weeks now, its not leaking.. even with the thrice-used washer.