wat speedo cog will i need in my toploader with a 3.45 rear end. atm its a 2.92 and has purple 17 toother in it, and speedo reads perfect. running 14inch 12 slotters, will be running 17s soon, i remember reading somewhere that wheel size made a difference??
have answered this a few times....
What you need to do is pull the speedo unit from the box, and ascertain the colour of the drive gear IN the box (as opposed to the driven gear on the speedo cable/sender)
The roll into a ford dealership with the Drive gear colour, box type, Diff ratio rim size and tyre profiles.
The have the table for selecting the right driven gear, and its pretty accurate.
With your electronic XD speedo, there is a calibration screw in the back. Buying a new sender cog will always be a little out, plus the cogs for a toploader with 3.5's cost about $45 these days! I think it's a white one?
I'm on the road at present, but I can post a pic next week. It's a real simple job. You'll have about +/- 40km/h of adjustment & saves you having to change cogs again with the new 17's.
No worries jas, I was actually being sarcastic....my bad! As you know, it's only a 2 min job......lost track of how may gearbox changes I've done.
But I totally agree, $45 for a stooopid plastic cog is a major ripoff. Hence, why I tell people to use their electronic speedo calibration screw on late model Falcons. Toploader cogs to suit low diff gears are way more expensive that those to suit a standard set of 2.7's etc. I'm beat as to why - someone obviously sees rare toploader parts as a way to cash in. C4 ones chew out the toploader drive spline on the output shaft....prick of a job changing that one!
Even worse is the Ford retail price for the toploader reverse light shifter switch which would cost $1.50 at Dick Smiths......they charge about $65.
Interesting on what you say about the C4 cogs chewing out the drive gear.
I was recently reading an article in Mustang monthly on this topic.. They actually spoke about several different driven gears. I will dig it out for ya.
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