GR Yaris I Broke my third Transmission at track 。this time GRMN close gear set

Have not see you around for a while now. Did you fix your engine yet?.
I don’t really track my GR Yaris at summer
Busy tracking with my other car
 

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@Diyman25 hi, even if not tracking your GR Yaris through summer, how many track hours have you done already on it since installing the Cusco hubs?
Reason I am asking: I am getting more and more issues shifting from 2nd to 3rd under hard acceleration. coming home from a track day where it did get worse and backing up to my garage I heard concerning noises coming from the drive train and a strange binding from the front diff. my bet is I will find some damage on gearhubs and the gearbox overall :-/
 
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@Diyman25 hi, even if not tracking your GR Yaris through summer, how many track hours have you done already on it since installing the Cusco hubs?
Reason I am asking: I am getting more and more issues shifting from 2nd to 3rd under hard acceleration. coming home from a track day where it did get worse and backing up to my garage I heard concerning noises coming from the drive train and a strange binding from the front diff. my bet is I will find some damage on gearhubs and the gearbox overall :-/
What is ur set up
Tire size , power wise (TQ)
 
On 2-3 difficult gear up shift
Is usually not the issue I have in this thread
More like drive error

On my experience Gr Yaris Syncro could. Be fragile and not helping when Toyota put a plastic shift pad in shift fork
 
On 2-3 difficult gear up shift
Is usually not the issue I have in this thread
More like drive error

On my experience Gr Yaris Syncro could. Be fragile and not helping when Toyota put a plastic shift pad in shift fork
it happens only on 2nd to 3rd, under load. maybe 1 of 5 shifts. sometimes I can reproduce, sometimes not.
end of last year I was coming home from a track day with a buddy of mine, same car, stock power. he got similar noises coming from gearbox and front diff as I have now. after few kms he got stuck with a completely locked drive train. result: 2nd shattered, torsen to pieces:
081889c3-f22b-48ef-bc33-f5497a52ee3f.webp

I will see what awaits me, in case the transmission dies on me, I will try to rebuild with the cusco hubs.
 
it happens only on 2nd to 3rd, under load. maybe 1 of 5 shifts. sometimes I can reproduce, sometimes not.
end of last year I was coming home from a track day with a buddy of mine, same car, stock power. he got similar noises coming from gearbox and front diff as I have now. after few kms he got stuck with a completely locked drive train. result: 2nd shattered, torsen to pieces:
View attachment 30478
I will see what awaits me, in case the transmission dies on me, I will try to rebuild with the cusco hubs.
That is some nasty failure on that lsd
 
To any one still follow the thread
Some thing update , in order to be fastest time attack machine in Taiwan
Choose some thing more suitable for track is need it
This time attack season I will move to 7speed Seq

Hope this thread will help whoever have transmission issue on their track Gr Yaris


Stay tune for more news on my time attack Gr Yaris
 

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Friend’s Gr Yaris car have same set of GCG28R like I do and push over 370whp and 45KG of TQ and 295/35/15 CRS with Cusco hub
Friend accidentally shit to 5th and stuck there , I tell them need to wait car to cool down , luckily car still have stock gear ratio
So car can finish circuit with 3-4 have decent improvement with new turbo

Car will be back with rebuild transmission and stock dual mass flywheel with upgrade pressure plate

U guys can see my opel speedster there
 

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Is very difficult to determined what is real cause of OE style Syncro hub failure
Main reason is definitely the torque
Other reason like tire size , flywheel frequency should be part of sub reason too
 

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on a side note: I attended a trackday this weekend, as a preventive meassure I decided to change the transmission oil after appr. 10tkms (which was just dark, but nothing extraordinary). while having the car stripped and on jack stands I decided to check the transmission mount. the 4 screws holding the aluminum bracket to the transmission body were completely loose - just slightly above hand tight. the screws going to the car body also very loose. I added a generous amount of blue loctite to all the screws and retightened. it solved 90% of my 2nd to 3rd upshift issue.
 
on a side note: I attended a trackday this weekend, as a preventive meassure I decided to change the transmission oil after appr. 10tkms (which was just dark, but nothing extraordinary). while having the car stripped and on jack stands I decided to check the transmission mount. the 4 screws holding the aluminum bracket to the transmission body were completely loose - just slightly above hand tight. the screws going to the car body also very loose. I added a generous amount of blue loctite to all the screws and retightened. it solved 90% of my 2nd to 3rd upshift issue.
Glad u find the issue of ur problem 👍
 
To any one still follow the thread
Some thing update , in order to be fastest time attack machine in Taiwan
Choose some thing more suitable for track is need it
This time attack season I will move to 7speed Seq

Hope this thread will help whoever have transmission issue on their track Gr Yaris


Stay tune for more news on my time attack Gr Yaris
What were your findings with the Cusco hubs? did those break as well before you changed to 7speed Seq?