Sirion / L701 Gearbox questions


I have a question just to confirm. Is impossible to found a gearbox from Sirion 1.3, but i found a gearbox from l701, I know that the boxes are not the same on the outside, but the gears could be used as spare parts for my gearbox?. I understand that yes, but if a charitable soul can confirm it, I will thank you.


Yes but they’re designed for half the power

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You can use the ratios but as Patrick has said they are used on an engine with half the power, you may get a bit of wheel spin but a closer ratio box over all.
Seeing as all gears except the gtti gears are the same width, they can be mixed and matched.
A cruel example is you could make a 5 speed full of first gear ratios.

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Unfortunately the inherent weekness in the k3/sirion gearbox is because the box was based on the existing 3cyl one then already 2 yrs in production, sure daihatsu engineers changed a few things mainly to do with fittment ie bellhousing , and gearing ie 4th gear and final drive. They have made some attempt to improve strength to cope with the extra torque of the K3 ie the 1st and 2nd gears on the output shaft but crucially 3rd gear imput and output gears have the same part numbers as the 3yl.

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Thank you very much for the answers

I understood that the third gear was especially weak, I never thought so much …

here some photos of the gears in the gearbox

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yeah there it is again dude , i’ve seen so many pics like this one . If the cuore box sits behind the EJ ie L701 go ahead and change third gears over . I buy new Daihatsu parts from Japan using you’ll be suprised just how cheap new parts are and they ship wordwide. Find your Daihatsu part numbers with

Would you say it is destroying istelf from load or heat and load? What oil? Look into something like Redline’s synthetic.

I think that it was broken by load, the oil level was correct. I was using Ravenol Full synthetic plus a liquimoly additive.

In the engine I use Redline (although I wanted to switch to Royal Purple) plus a ceratec.

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