Grinding MT 1st gear only

[2bz]

Shifting down to 1st gear has just started to grind. No other gears grind up or down. Did a gear oil change with Mobil 1 75W90 about 6 months ago.

Syncro on 1st going? Clutch dragging? Shift linkage? Something else?

Thanks.

[2bz]

Looks like the consensus is synthetic GL-5 lube is shit for Toyota MTs. Going to try swapping it out with some GL-4 Dino.

[komichal]

Just make sure you go for the original Toyota 75W.

I tried Valvoline 75W90 GL4 (replacing the original oil after nearly 200tkm). It was OK but the gearbox started to grind occasionally and the shifting from 1 to 2 in cold weather (-10 Celsius) was hard.

So after a year I changed it to Elf 75W80 (yes, 80 - recommended by Elf) GL4. Cold shifting problem is gone but slight grinding occurs now and then. I would say it is acceptable but next time I would definitely go for Toyota original oil. I have no problem with using non-Toyota liquids for engine oil or coolant or brakes (as long as they match the required specs) but this gearbox seems to be a real gourmet.

Do not make the same mistake as I did and go for original oil directly. It costs a bit more but it is worth it!

[dogsridewith]

Does this Yaris even have a first gear synchro? Very tight w/ whatever fluid was there when I got the car. Same way w/ Mobil 1 75/90. Wondered why the new Mobil 1 had a faint odor of that rank gear oil smell. Seems like a candidate for counterfeiting.

[tmontague]

Before I had my clutch type LSD I had good luck with Amsoil MTG, it was smoother than redline MT-90 that untried before it handled the cold really well. It is a proper GL-4 iirc.

The MTG wasn't a good fluid for my LSD so I now use Redline MT-85 and no grinding issues really, and it is a great fluid for a clutch type LSD.

As others stated, stick with a proper GL4 and you should be fine

[dogsridewith]

2007 Owner's Manual for USA/Canada specifies API GL-4 or GL-5 w/ viscosity of SAE 75W-90

[2bz]

I bought CRC Sta-Lube GL-4 85W90 conventional (dino). Should be able to replace the Mobil 1 within the next few days.

[Mask Rider Blac]

We use this...60331https://uploads.tapatalk-cdn.com/20190307/e31f1b50d5f7d2bc90d3ab80873a134e.jpg

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[suprf1y]

I'm surprised nobody here uses Synchromesh MTF. It's a GL4 and especially good for cold temperature and fuel economy applications, and it's fixed a bad 1-2 grind for me a number of times

https://www.pennzoil.com/en_ca/products/other-oils-fluids-fuel/manual-transmission-fluids-axle-oils/synchromesh-manual-transmission-fluid.html#iframe=L3NvcHVzL3Blbm56b2lsLzIwMTZuZXdz bGV0dGVyLz9sb2NhbGU9ZW5fY2E

[IllusionX]

I'm surprised nobody here uses Synchromesh MTF. It's a GL4 and especially good for cold temperature and fuel economy applications, and it's fixed a bad 1-2 grind for me a number of times

https://www.pennzoil.com/en_ca/products/other-oils-fluids-fuel/manual-transmission-fluids-axle-oils/synchromesh-manual-transmission-fluid.html#iframe=L3NvcHVzL3Blbm56b2lsLzIwMTZuZXdz bGV0dGVyLz9sb2NhbGU9ZW5fY2EI believe I've used RoyalPurple Synchromax in my transmission after trying Castrol syntec 75W90 and was pretty bad for the transmission.

RoyalPurple was not better, and obviously the wrong type of oil. Drove it a while, then change it to Amsoil GL4.

Transmission has been better since, but I still get the occasional grind shifting into 1st while not 100% stopped. But I'm still grinding shifting from 3rd to 5th when reving high.

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[suprf1y]

I believe I've used RoyalPurple Synchromax in my transmission after trying Castrol syntec 75W90 and was pretty bad for the transmission.



How was it bad for the transmission?

[IllusionX]

How was it bad for the transmission?RP Synchromax? It's not the right oil for this transmission. It would grind shifting into 1st, and 3 4 and 5th high reving. Just go with proper oil and you shouldn't have problems.



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[2bz]

Changed to Dino GL-4. No more grinding. Life is good.

[stykerdk]

Or use this.
https://www.amazon.com/gp/product/B00QPCL7ZE?pf_rd_p=1581d9f4-062f-453c-b69e-0f3e00ba2652&pf_rd_r=WTZ1BAT3K61MGZAFAK4E

[dogsridewith]

Changed to Dino GL-4. No more grinding. Life is good.Will try to replicate. Why did you opt for the Dino brand of GL-4?

re: 2-1 grind w/ the Mobil 1--was this shift also quite stiff? (Mine takes too much push to happen, but there isn't an audible grind or bite felt in the shift lever.)

[2bz]

Will try to replicate. Why did you opt for the Dino brand of GL-4?

re: 2-1 grind w/ the Mobil 1--was this shift also quite stiff? (Mine takes too much push to happen, but there isn't an audible grind or bite felt in the shift lever.)

Dino as in dinosaur (conventional, not synthetic). It was CRC Sta-Lube gear oil. Yes, on the stiff. But I had grinding on 2>1 and occasionally 2>3. Nice and smooth all around now.

[dogsridewith]

and, per your #7 post, 85w90 weight...which sould be a little thicker at low temperatures than the other oils mentioned in this thread.