Hi guys,

I have a 5 speed 4L AU ute, I'm about to swap out my standard 3.23 diff gears for 3.89's. Can anyone please help me out as to which speedo drive i will have to change to for a correct reading on the dash, or if it isnt that simple. I'm pretty sure that it has a green speedo drive in it at the moment, which is a 21 tooth.

Thanks in advance.

As far as I am aware there was no "range" of cogs available for that transmission.
Ford did not release a 3.89 so would not have a cog for that anyway.
Someone out here may be able to confirm that.
The guys I am aware of who change diffs had to alter their speedo via an electronic module, which, may be because cogs are not available.

Await more responses for further info....

The info I herd was on earlier cars ea-el you could only buyup to a 3.7 gear speedo drive anything higher you had to guess your speed or get a eleco speedo calibrator