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75 Posts
Discussion Starter · #1 ·
So I am the sort of person that likes to know technical stuff, just for the sake of knowing and finding out.

I've been hunting around for info on the Transmission that is used in the Fiesta ST, but there is very little to be had. I find this a touch surprising given the cars popularity with the public and motoring media.

Facts and info Ive found so far:

Fiesta ST uses a Ford IB6 6 speed gearbox. I'm guessing an evolution of the solid IB5?
Different box to what the Focus ST uses (Borg Warner).
Unknown max HP/Torque tolerance.
A variant of this box is used in the Fusion. Saw some possible info that the Europeans get it on the 1.0L ecoboost.
No major or systemic issues reported with this transmission yet?
Gear ratios of the IB6:
I 3.727 (14.24)
II 2.098 (8.01)
III 1.357 (5.18)
IV 1.03 (3.93)
V 0.821 (3.14)
VI 0.69 (2.64)
Final drive: 3.82

Comparison with the IB5: (Ratio's taken from a 2011 WT)
I 3.583 (14.58)
II 1.926 (7.84)
III 1.281 (5.21)
IV 0.951 (3.87)
V 0.756 (3.08)
Final Drive: 4.07

Interesting that with the final drive ratio taken into account, the ratio's are quite similar for 1st through 5th.
1st and 3rd are taller in the IB6 than the IB5, 2nd, 4th and 5th Shorter. 6th a nicely taller overdrive.

908 Posts
The transmission is a Ford/Getrag joint project and as far as I can tell is not based on an existing transmission, rather it was an exercise in rightsizing so if you abuse it enough to break it, just about anything could break because nothing is significantly stronger than the weakest link.

So far it seems fairly strong.

2 Posts
The IB5 in the MK6 ST was know to turn to butter... drive shaft through bell housing style.

Hope the new box is more solid.
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