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Speedometer Calibration?
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Joined: Dec 2003
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From: Lake Forest, CA
Speedometer Calibration?
I have a 2002 F250 Super Duty 4x4 Crew cab 7.3L automatic transmission that I put a 3" lift on and larger tires and rims. The speedometer is now off by roughly three or four miles per hour. Does anyone know how I can go about calibrating it back to being accurate? I had someone at a Ford shop tell me it couldn’t be done on this truck.
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From: Allen, Tx
How big are your tires? The WDS (Worldwide Diagnostic System) computers that dealers use to re-flash/recalibrate your PCM only have a certain range of "valid" tire sizes. You have to select a tire size from a drop down menu and I think the biggest that it will have in its database is either the 295/75R16 or the 315/75R16, can't remember. They reprogrammed my 2002 F150 from 255/70R16's to 235/75R16's just fine though. If your tires are bigger than that, you'll have to get a truspeed from Superlift.
Tuned
Joined: Nov 2002
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From: Newburgh, NY
Don't want to get too technical but when you change a tire or gear your effectively changing the ratio and by doig that you make the difference between the actual speed and the indicated speed (speedo reading) variable. So at 10 mph you may only be going 1 mph more then the speedo reads but at 60 mph it could be 6 mph more. Gear swaps make a much larger impact.
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From: Ventura County, CA
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Cargo Master
Joined: Oct 2003
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From: Jefferson, Iowa
You do not need to change the speedo for a gear change, because the sensor is on the ring gear. You could put 4.56's in there and the speedo would still be fine in the superdutys.
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From: IN FRONT OF YOU
Originally posted by 78fordman
You do not need to change the speedo for a gear change, because the sensor is on the ring gear. You could put 4.56's in there and the speedo would still be fine in the superdutys.
You do not need to change the speedo for a gear change, because the sensor is on the ring gear. You could put 4.56's in there and the speedo would still be fine in the superdutys.
You don't need to for a gear change, but for a different tire size you do.
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