6 speed conversion?!

[Iddzyy]

Right guys,

I've had gearbox issues for a month. I'm looking at having to spend a substantial amount of money on reconditioning my current 5 speed, 1.6 VVTI 2008 Toyota Auris. I would like to know if anyone has changed the box to a 6 speed (get some better mway mpg hopefully) and how to go about it. 

Is it as simple as changing the box and probably the selector n links? Which box would fit? Does anyone know what code for the part? 

 

Thanks in advance. 

[Cyker]

If this is the 6-speed from the 1.33 gearbox, I personally wouldn't as it's more fragile than the 5-speed. The one in my Mk2 Yaris has the honour of being the first failed gearbox I've experienced.

I'm pretty sure it wouldn't fit on the 1.6 anyway, but that is something people like flash who actually know stuff would have to advise!

[furtula]

I'm not sure about exact dates, but  mid 2009 is when Auris got 6th speed on 1.6 engine, and also when 1ZR-FAE replaced 1ZR-FE. But being based on 1ZR-FE, might mean the gearbox sits. 

I don't think you will get any better MPG due to high wind resistance when using 6th. Only advantage might be some 200-300 rpm drop in 6th speed, as opposed to 5th, on highway.

I doubt anyone here can give you a straight answer, if you are lucky and have access to the gearboxes, you can make a quick cardboard template of old and new, and see if it sits.  Looks similar, but can't be sure without a template.

There's also the difference in clutch setup, old one seems to be using a normal fork, 6 speed seems to slave cylinder inside the clutch (must be nice when it start to leak).

I think i read on someone doing similar thing on Avensis forum, but it was a diesel. No issues apart from shift up/down getting a little confused as it does not know there's a 6th gear.

 

Left is 6 speed, right is 5 speed.

 

[Cyker]

Ah that's good info, I didn't know the 1.6 had a 6-speed - I thought it wasn't until it was replaced with the 1.2T when it got a 6-speed! (Shows how much I know!)

The 6-speed in my Yaris also used a Concentric Slave Cylinder, basically slave cylinder and release bearing all integrated into one unit so no need for a release fork and a big hole in the bell housing. Was as expensive as the 2-piece clutch kit from Toyota so I ended getting one from Fensport for a third the cost, but I think it's come down now (Now that I no longer have the car!!  )

If you feel the car has enough grunt to push it in the 6th gear (I don't even know what the ratios are!) then maybe it could work, but in the Yaris 6th gear was purely as a motorway cruising gear; Even a slight incline forced me to downshift as the engine couldn't hold its speed, and I had similar pedal input vs the same speed in 5th, so I suspect it wasn't saving me much fuel...!

[flash22]

the 6 speed uses a different clutch and flywheel and possibly starter early 5 speed uses an  external slave with a fork the 6 speed uses a concentric slave/throw out bearing

the bell housing bolts are in a different pattern iirc

A lot of pain for little gain

[Iddzyy]

Thanks for the replies. Reading the replies I guess it's not worth the headache so I'll leave it.

 

More than likely I'll get the 5 speed gearbox reconditioned and then put the car on sale

[Cyker]

I think that's wise; I find for major changes to an available spec like this, it's often cheaper and easier to just sell what you have and buy one that already has what you wanted!  

[tavy]

  I think a better idea is upgrading 1.4 and 1.6 petrol engines gearboxes, changing 5-th gear pinions. 5-th gear indead is too close to 4-th, on the motorways is not good at all, it revs the engine too much...

  After some researches I found that the 1.4 diesel gearbox is the same, differs only 5-th gears pinions, that have a lower ratio, and gear box differential. So, the solution I think is to change 5-th gear pinions, but until I don't find a damaged diesel engine gearbox to recover 5-th gear pinions I'm not 100% sure. After this modiffication, allmost 10 mph can be earn in 5-th gear. 

[Rhymes with Paris]

11 hours ago, Cyker said:

I think that's wise; I find for major changes to an available spec like this, it's often cheaper and easier to just sell what you have and buy one that already has what you wanted!  

I agree, remembering when I had my old lexus is 200, talking to other owners spending large amounts of money and time chasing another 50 BHP on top of the standard 150 BHP.

Easier and cheaper was to buy a is 300 with 200 BHP in the first place.

[tavy]

  Selling your beloved car is not an option !   Upgrading is...

   

[flash22]

its 5th and 6th that tend to fail first if you change 5th you also need to sort out the driven gear

[furtula]

On 6/4/2022 at 7:58 AM, tavy said:

  I think a better idea is upgrading 1.4 and 1.6 petrol engines gearboxes, changing 5-th gear pinions. 5-th gear indead is too close to 4-th, on the motorways is not good at all, it revs the engine too much...

  After some researches I found that the 1.4 diesel gearbox is the same, differs only 5-th gears pinions, that have a lower ratio, and gear box differential. So, the solution I think is to change 5-th gear pinions, but until I don't find a damaged diesel engine gearbox to recover 5-th gear pinions I'm not 100% sure. After this modiffication, allmost 10 mph can be earn in 5-th gear. 

I think the final drive gear ratio is not same on diesel like on gasoline. So it's not really worth it.

Even if you change the 5th gear only to get a drop on RPM's, it will probably cause the car to bog down a bit, and increase consumption.

Best solution would be to actually calculate the ideal gear ratio to benefit from good mpg, and lower rpm at higher speeds, and get only that sprocket made, for 5th gear.

 

As others said, not worth it.  I would just sell the car and get a newer one (but from 2012, or when was it, that they fixed the vvti issue).

[tavy]

9 hours ago, furtula said:

I think the final drive gear ratio is not same on diesel like on gasoline... 

Of course it isn't. 

9 hours ago, furtula said:

Even if you change the 5th gear only to get a drop on RPM's, it will probably cause the car to bog down a bit, and increase consumption... 

  If you get 400 ... 500 rpm drop in 5th gear, gain in consumption will be aprox 0.5 liters at 100km on motorway driving at 130 km/h, and is not neglectable at all. Plus, is not so difficult to change a 5th gear pair of pinions, there's no need to remove entire gear box, it's enough to hoist the car, drain the gear box oil and remove the 5th gear box cover.