speedometer correction help please

[tigercat]

hi i recently swapped a 3.73 ls in place of my stock 3.08 open rear axle. my question is how can i fix my speedometer reading because im tired of trying to guess my actual speed. any help is appreciated

 

[Flip4ford]

You will need to change your speedo gear. it is on the transfer case (at the end of the speedo cable) Takes 5 minutes to change-- Here is a link with all the info you need.... http://www.therangerstation.com/tech_library/Speedogear.html

 

[diamondback2k9]

I think you need to have it calebrated somewhere and its not something you can do it your-self you need to have a special machine.

 

[Maniak]

On his '92, ist just the driven gear that needs to be changed.. takes almost no time.

In short though, if you "ONLY" change the gears, and not the tires size too, your speed is now running 18% off. Your speed gear needs to be 18% bigger than what you have in there now.

With that big of a change you may need a speedo gear adapter. Its thing with 2 gears in it to allow you to change the speedo calibration farther than you can do with just the gear change.

If your changing tire size too, then it won't be as big as a change.

~Mark

 

[Roadrunner440]

take a GPS with you or find a friendly cop who can clock your speed for you and just learn what speed corresponds with what reading on the speedo. its not that hard to do. like in my explorer 27 on the speedo = 30 km/h, 45=50, 100=110. i just drive like that.

 

[Maniak]

It takes 5 minutes to change the Gear out. Just swap it out next time your doing an oil change, while your waiting for the oil to drain.

What worries me is the amount of change. an 18% change IIRC is 4 teeth, which means depending on where you are now, you may not be able to get the correct gear.

'Course, since you started with a factory ratio, and are going to another factory ratio, they must have a gear for that.

~Mark

 

[tigercat]

well if i go to pick n pull can in get the gear out of a 90-94 explorer with an auto tranny and 3.73 gears