C series gearbox - interchangeable gears - Toyota Yaris Forums

TMX26 · 05-06-2020, 08:02 AM

I’ve looked into this and I can’t seem to find any information about interchangeable gears between C series gearboxes - only interchangeability of the gearboxes themselves.

Specifically for the Yaris 1.5 TS, I find the 4th gear ratio too long compared to the 3rd, and the 5th gear too short compared to fourth. The solution would be a shorter 4th gear.
As far as I know, the 4th gear ratio on the original 1.5 TS gearbox is 1.031. Fitting a shorter OEM 4th gear from another C series gearbox would be an obvious solution.
But for even closer ratios, I was wondering if one could swap the first 5 gears from the C160 gearbox bolted to 20V 4A-GEs into the gearbox of a 1.5 TS (since both are C series gearboxes). The 1st 5 ratios of that gearbox are very close, while still allowing the car to achieve its top speed (loosing only a little in fuel economy). Is this possible ?

Again, I am sorry if this was asked many times before. Thank you for your responses, anything will be appreciated.

Desircustoms · 05-22-2020, 02:08 AM

No clue if c160 gears will fit into a c50, can't help you with that. But here's a playlist that might be helpful.

https://www.youtube.com/playlist?lis...-_QKttWdJ3Sk3I

Armstrong has fitted all 6 c60 gears into a c50 housing.

CrankyOldMan · 05-22-2020, 01:55 PM

Weird, I swear I replied to this post.

ArmstronRacing indeed has the definitive guide for gear swaps. I've done some research as well but didn't do a very good job of documenting it. Here's a quick summary:

* The C5*/C6* family is generally interchangeable, the C15*/C16* family is generally interchangeable, but the families are not. I.e. the C15x is narrower and has shorter shafts than the C5*.

* 1st and 2nd gear are fixed to the input shaft. Most have the same 2nd gear ratio. If you want a different 1st gear ratio, you have to change the input shaft.

* The final drive is fixed to the pinion shaft.

* There a limited number of ratios that can physically fit into the gear space, and a limit to the number of combinations that make sense for the RPM and common speed limits of a given market. Fuel economy also plays into that, I suspect, so they target a certain fuel economy by matching a gear ratio to the optimum engine speed to reach a target cruising speed.

* The differentials and differential ring gears are definitely not compatible between C5* and C15*, and are not necessarily compatible inside of a family, even with the "same" model. I.e. the Yaris C50 uses the same gear ratios as the xD C50 but they use different differential bodies and gear rings.

I found a great site with USDM gearbox parts info as well: mmerlinn.com. They list the ratios, shaft diameters and all the critical info you need to figure out what can physically be swapped. This may or may not apply to you though because non-USDM gearboxes often have very different ratios for the reasons above.

05-06-2020, 08:02 AM	#1
TMX26 Drives: Soon Join Date: May 2020 Location: Switzerland Posts: 2	C series gearbox - interchangeable gears I’ve looked into this and I can’t seem to find any information about interchangeable gears between C series gearboxes - only interchangeability of the gearboxes themselves. Specifically for the Yaris 1.5 TS, I find the 4th gear ratio too long compared to the 3rd, and the 5th gear too short compared to fourth. The solution would be a shorter 4th gear. As far as I know, the 4th gear ratio on the original 1.5 TS gearbox is 1.031. Fitting a shorter OEM 4th gear from another C series gearbox would be an obvious solution. But for even closer ratios, I was wondering if one could swap the first 5 gears from the C160 gearbox bolted to 20V 4A-GEs into the gearbox of a 1.5 TS (since both are C series gearboxes). The 1st 5 ratios of that gearbox are very close, while still allowing the car to achieve its top speed (loosing only a little in fuel economy). Is this possible ? Again, I am sorry if this was asked many times before. Thank you for your responses, anything will be appreciated.

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05-22-2020, 02:08 AM	#2
Desircustoms Drives: 06 Yaris RS MT Join Date: Jun 2018 Location: Ottawa, Ontario, Canada Posts: 52	No clue if c160 gears will fit into a c50, can't help you with that. But here's a playlist that might be helpful. https://www.youtube.com/playlist?lis...-_QKttWdJ3Sk3I Armstrong has fitted all 6 c60 gears into a c50 housing.

05-22-2020, 01:55 PM	#3
CrankyOldMan 2ZR swap. DO IT! Ask how! View User's Garage Drives: 09 Meteoric Metallic HB Join Date: Feb 2011 Location: West Michigan Posts: 2,333	Weird, I swear I replied to this post. ArmstronRacing indeed has the definitive guide for gear swaps. I've done some research as well but didn't do a very good job of documenting it. Here's a quick summary: * The C5/C6 family is generally interchangeable, the C15/C16 family is generally interchangeable, but the families are not. I.e. the C15x is narrower and has shorter shafts than the C5. 1st and 2nd gear are fixed to the input shaft. Most have the same 2nd gear ratio. If you want a different 1st gear ratio, you have to change the input shaft. * The final drive is fixed to the pinion shaft. * There a limited number of ratios that can physically fit into the gear space, and a limit to the number of combinations that make sense for the RPM and common speed limits of a given market. Fuel economy also plays into that, I suspect, so they target a certain fuel economy by matching a gear ratio to the optimum engine speed to reach a target cruising speed. * The differentials and differential ring gears are definitely not compatible between C5* and C15*, and are not necessarily compatible inside of a family, even with the "same" model. I.e. the Yaris C50 uses the same gear ratios as the xD C50 but they use different differential bodies and gear rings. I found a great site with USDM gearbox parts info as well: mmerlinn.com. They list the ratios, shaft diameters and all the critical info you need to figure out what can physically be swapped. This may or may not apply to you though because non-USDM gearboxes often have very different ratios for the reasons above.