Synthetic Gear Oil - Toyota Yaris Forums

redyaris2012 · 09-26-2015, 09:03 PM

After 23,000 km, decided to replace the factory gear oil on my 2012 5 speed manual with synthetic Royal Purple. Expensive for 2 bottles each at 946 ml but if it performs better and is more efficient, than it justifies the cost. Well, after a few days of driving, I have noticed shifting is smoother and changing from 2nd to 1st is really smooth. Convinced to always use synthetic. The manual only states changing gear oil only under extreme conditions. My 1980 Corolla had 285,00km and I never changed the gear oil and the 4 speed transmission never failed.

2012 Toyota Yaris
2001 Subaru Forester

IllusionX · 09-26-2015, 11:44 PM

Gear oil should be changed every 65000km. That includes AWD differentials.

But then, if it works for you. I switched to Castrol Syntec 75w90 and it was the worse mistake I did. Synchros would grind under high rpm shifting.

I briefly used RP synchromesh, and it helped, but still wasn't good, so now I have AmsOIL 75w90 and its working as it should. Still grinds from time to time, but that's probably because my synchro are already damaged...

Sent from my A0001 using Tapatalk

Thirty-Nine · 09-28-2015, 04:21 PM

I'm using Red Line synthetic in my trans. I recently noticed a slight occasional grinding going from 1st to 2nd, but I don't know of the two things coincide.

CoryM · 09-28-2015, 09:07 PM

I suggest running the OE specification for A/T and M/T. The reason being you have friction surfaces which are designed to work with a certain fluid. If you make that fluid more or less slippery, the friction surfaces will increase or reduce their performance.

In the case of M/Ts, you have synchronizer rings. These are little brakes that use friction to slow the spinning parts down enough that you can change gears without grinding. If you use slippery synthetic oils the syncronizers will not work as well; making it take longer to slow the rotating parts down.

I tried two different synth oils in my Yaris since the shift feel is so bad, and because I'd heard a lot of people on the forum have positive results. I ended up going back to non-synth oil within a few days because I could feel the syncronizers not working as well. The generally accepted life of uncontaminated gear oil is 100,000km to infinity (many OEM suggest there is no need to change). That being said, I have never personally done oil analyses on gear oil.

Frank Necrosis · 10-01-2015, 01:17 PM

After putting 15,000 miles on the car, I switched to Redline in hopes of improving the shifting. It helped for a while, but after about 10,000 miles, the shifts were worse than ever. When I drained it, it was like water coming out of the case. The Redline seemed to break down in spectacular fashion.

I ran Mobile 1 for about 30,000 miles and it did ok. Mobile 1 was nice during the sub 0 degree F temps we had last winter. The trans would go into gear without much of a fight before it warmed up. Over the summer, the shifting became difficult again, so I swapped out the Mobile 1 for Lucas. Mobile 1 wasn't in stock, and Lucas seems to make good products. So far so good.

Thirty-Nine · 10-05-2015, 08:09 PM

Quote:

Originally Posted by CoryM

I suggest running the OE specification for A/T and M/T. The reason being you have friction surfaces which are designed to work with a certain fluid. If you make that fluid more or less slippery, the friction surfaces will increase or reduce their performance.

In the case of M/Ts, you have synchronizer rings. These are little brakes that use friction to slow the spinning parts down enough that you can change gears without grinding. If you use slippery synthetic oils the syncronizers will not work as well; making it take longer to slow the rotating parts down.

I tried two different synth oils in my Yaris since the shift feel is so bad, and because I'd heard a lot of people on the forum have positive results. I ended up going back to non-synth oil within a few days because I could feel the syncronizers not working as well. The generally accepted life of uncontaminated gear oil is 100,000km to infinity (many OEM suggest there is no need to change). That being said, I have never personally done oil analyses on gear oil.

I'm using the right spec: 75W90 GL-4, although it is synthetic. I am noticing a slight grind during the 3-2 downshift (no where else). Never noticed it before. Hmm ...

SirDigby · 10-05-2015, 11:59 PM

that's strange. I've never heard of such things. I was going to change my m/t fluid soon. I've always had Hondas before, which use their own fluid; synthetic I believe. no quality aftermarkets available that I know of. i'm going to do a little more research now....

IllusionX · 10-06-2015, 12:04 AM

I've never had issues with down shifts. Maybe because I always double clutch my downshifts. But I could grind 3-4 and 4-5 upshifts at high RPM with the synthetic oil.

Sent from my A0001 using Tapatalk

09-26-2015, 09:03 PM	#1
redyaris2012 I've made a post! Drives: 2012 yaris sedan Join Date: Oct 2014 Location: Ontario, Canada Posts: 1	Synthetic Gear Oil After 23,000 km, decided to replace the factory gear oil on my 2012 5 speed manual with synthetic Royal Purple. Expensive for 2 bottles each at 946 ml but if it performs better and is more efficient, than it justifies the cost. Well, after a few days of driving, I have noticed shifting is smoother and changing from 2nd to 1st is really smooth. Convinced to always use synthetic. The manual only states changing gear oil only under extreme conditions. My 1980 Corolla had 285,00km and I never changed the gear oil and the 4 speed transmission never failed. 2012 Toyota Yaris 2001 Subaru Forester Last edited by redyaris2012; 09-26-2015 at 09:17 PM. Reason: Add vehicle list.

09-26-2015, 11:44 PM	#2
IllusionX It's the illusion you see View User's Garage Drives: 07 Yaris Sedan Aero Join Date: Oct 2006 Location: Brossard, QC Posts: 3,888	Gear oil should be changed every 65000km. That includes AWD differentials. But then, if it works for you. I switched to Castrol Syntec 75w90 and it was the worse mistake I did. Synchros would grind under high rpm shifting. I briefly used RP synchromesh, and it helped, but still wasn't good, so now I have AmsOIL 75w90 and its working as it should. Still grinds from time to time, but that's probably because my synchro are already damaged... Sent from my A0001 using Tapatalk __________________

09-28-2015, 04:21 PM	#3
Thirty-Nine Small cars are a big deal View User's Garage Drives: 2007 Yaris Liftback Join Date: Feb 2006 Location: Portland, OR Posts: 3,144	I'm using Red Line synthetic in my trans. I recently noticed a slight occasional grinding going from 1st to 2nd, but I don't know of the two things coincide. __________________ Subcompact Culture: The Small car blog

10-06-2015, 12:04 AM	#8
IllusionX It's the illusion you see View User's Garage Drives: 07 Yaris Sedan Aero Join Date: Oct 2006 Location: Brossard, QC Posts: 3,888	I've never had issues with down shifts. Maybe because I always double clutch my downshifts. But I could grind 3-4 and 4-5 upshifts at high RPM with the synthetic oil. Sent from my A0001 using Tapatalk __________________

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09-28-2015, 09:07 PM	#4
CoryM Drives: 2009 5-door, 5-speed Join Date: Sep 2011 Location: White Rock BC Posts: 687	I suggest running the OE specification for A/T and M/T. The reason being you have friction surfaces which are designed to work with a certain fluid. If you make that fluid more or less slippery, the friction surfaces will increase or reduce their performance. In the case of M/Ts, you have synchronizer rings. These are little brakes that use friction to slow the spinning parts down enough that you can change gears without grinding. If you use slippery synthetic oils the syncronizers will not work as well; making it take longer to slow the rotating parts down. I tried two different synth oils in my Yaris since the shift feel is so bad, and because I'd heard a lot of people on the forum have positive results. I ended up going back to non-synth oil within a few days because I could feel the syncronizers not working as well. The generally accepted life of uncontaminated gear oil is 100,000km to infinity (many OEM suggest there is no need to change). That being said, I have never personally done oil analyses on gear oil.

10-01-2015, 01:17 PM	#5
Frank Necrosis Drives: 2012 Yaris L MT Join Date: May 2012 Location: Youngstown, Oh Posts: 66	After putting 15,000 miles on the car, I switched to Redline in hopes of improving the shifting. It helped for a while, but after about 10,000 miles, the shifts were worse than ever. When I drained it, it was like water coming out of the case. The Redline seemed to break down in spectacular fashion. I ran Mobile 1 for about 30,000 miles and it did ok. Mobile 1 was nice during the sub 0 degree F temps we had last winter. The trans would go into gear without much of a fight before it warmed up. Over the summer, the shifting became difficult again, so I swapped out the Mobile 1 for Lucas. Mobile 1 wasn't in stock, and Lucas seems to make good products. So far so good.

10-05-2015, 11:59 PM	#7
SirDigby View User's Garage Drives: 2007 yaris 3 door Join Date: Sep 2015 Location: Denver, Colorado Posts: 1,000	that's strange. I've never heard of such things. I was going to change my m/t fluid soon. I've always had Hondas before, which use their own fluid; synthetic I believe. no quality aftermarkets available that I know of. i'm going to do a little more research now....