[updated:LAST EDITED ON 04-Jun-02 AT 04:35 PM (EST)]I am new to this site so I don't if this is the correct place to be asking this.

Can anyone please help me? I am installing a 4.10 gear here shortly and before I do so I am wondering "how" or "what" I need to be doing about recalibrating the speedometer with the gear? I have been told that you can buy a small gear to replace in the tranny but other say I will need to get a chip for it. I dont want to go the route of a chip because of early future modifications. Any suggestions or any information would be a great help.

The gear is going in a '96 explorer

 

[updated:LAST EDITED ON 05-Jun-02 AT 08:07 PM (EST)]On your '96 you can replace the plastic gear at the end of your vehicle speed sensor (VSS). Your VSS can be found at the end of your transfer case if you have a 4x4 or the end of your transmission tail shaft if yours is 2WD. The gear costs about $8 at Ford and takes about 5 minutes to R&R. To know which gear to get, you will have to take into account any change in tire size and the gear ratio change from stock. What ever the overall ratio change is will determine the proper gear to go with. For instance if you put larger tires that are the same ratio taller than your stock tires as the ratio your gear ratio changed from then it will balance out and you won't need a new speedometer gear. If your tires are still the stock size and all you are changing is the gear ratio then divide 4.10 by your old gear ratio and multiply it by the number of teeth on your original speedometer gear. Get one with as close as you can get to the new number of teeth that is identical in length to the original one. Ford sells two different sizes (one for manual & one for automatics). They aren't interchangeable. When I went from 30" tires to 32" tires, I had to swap my 20 tooth gear out for a 19 tooth gear. This had the same affect as going to a lower gear ratio than stock which is the opposite of what you are probably doing. If you are going from a numerically lower number to a 4.10 then you will need a gear with more teeth if you don't change the tire size.

This only applies to Explorers built through '97. Beginning in '98 Ford eliminated the VSS on the transmission/transfer case and started using the rear ABS sensor. It can't be changed (easily anyway) and the only way to recalibrate these speedometers is by installing a chip or having Ford use their computer to do it for about $75-$100 depending on dealer.

 

Thanks for all the help, now I can get started installing the gear.