Re-Calibrating Speedometer??
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Lead Driver
Joined: Feb 2000
Posts: 5,373
Likes: 46
From: Palm Bay, Florida
Re-Calibrating Speedometer??
First off this is NOT for my SuperDuty.
It IS for my '03 Ranger 3.0 with 5speed AUTOMATIC trans.
I bought the truck in October and discovered it has the (optional) 4.10.1 gears.
I see absolutely NO reason to spin this little engine at nearly 3k rpm
at highway speeds.
I have my F350 7.3 S/D for any heavy hauling I need to do, the MOST weight I'd ever tow with the Ranger would be around 1k lbs
I'd like to swap to a 3.55.1 gear AND recalibrate the speedo.
I have asked on the Ranger forum how the re-calibrating is done nowadays-back in the day we used to just change the plastic gear on the end of the speedo cable.
No one seems to know......
It IS for my '03 Ranger 3.0 with 5speed AUTOMATIC trans.
I bought the truck in October and discovered it has the (optional) 4.10.1 gears.
I see absolutely NO reason to spin this little engine at nearly 3k rpm
at highway speeds.
I have my F350 7.3 S/D for any heavy hauling I need to do, the MOST weight I'd ever tow with the Ranger would be around 1k lbs
I'd like to swap to a 3.55.1 gear AND recalibrate the speedo.
I have asked on the Ranger forum how the re-calibrating is done nowadays-back in the day we used to just change the plastic gear on the end of the speedo cable.
No one seems to know......
Lead Driver
Joined: Jun 2003
Posts: 8,298
Likes: 24
From: Damon (South East Texas)
There are inline electronic modules that can be installed/adjusted to change the pulse counts of the VSS as read by the PCM. You may want to look into this option. Here a couple I have found: Superlift Truspeed (limited availability; I believe the #33002 is for your app) and Classic Instruments SN74 (available; universal). There are both shown in the Summit Racing online catalog. I was looking at the Truspeed modules before the Auto Enginuity was available with the tire size calibrator. I ended up using the Hypertech Speed Calibrator, but it is not available for your Ranger. Hope this helps. 
Hotshot
Joined: Jan 2011
Posts: 18,849
Likes: 179
From: Puget Sound
This is pre-OBDII, so AE is no help. Your truck was made when the national speed limit was 55, so the high RPMs are no surprise - my '92 Toyota P/U ran 4000 RPM at 75 MPH.
The sensor is pre-differential?
The sensor is pre-differential?
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Lead Driver
Joined: Feb 2000
Posts: 5,373
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From: Palm Bay, Florida
Not sure........I was told that a dealer can change/calibrate the speedo with THEIR computer.......not sure if this is true either......
Cargo Master
Joined: Mar 2006
Posts: 2,502
Likes: 2
From: Bend Oregon
I'd call the dealer, I believe they can change the gear ratio in the pcm. Or look at tuners, I think superchips made one for the 04 ranger that had a gear ratio selector. Might be fun to tweak the ranger.
Or keep the deep gears and Pre runner it with some 35's.
Or keep the deep gears and Pre runner it with some 35's
.
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,697
Likes: 2,619
From: SE Florida
I can make your speedometer work correctly with the new ratio sitting here at my computer. DONE. Go ahead and change the gears. The speedo will be exactly as accurate with the new ratio as it is right now.
The Vehicle Speed Sensor (VSS) reads the rotational speed of the rear axle shafts. Changing the rear axle doesn't change how fast the axle shafts rotate for any given speed, so the reading on the speedometer won't change when you change gears. If you change tire size you have to recalibrate the speedo, but not when you change gears.
The Vehicle Speed Sensor (VSS) reads the rotational speed of the rear axle shafts. Changing the rear axle doesn't change how fast the axle shafts rotate for any given speed, so the reading on the speedometer won't change when you change gears. If you change tire size you have to recalibrate the speedo, but not when you change gears.
Hotshot
Joined: Jan 2011
Posts: 18,849
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From: Puget Sound
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Lead Driver
Joined: Jun 2003
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From: Damon (South East Texas)
It is my understanding that a '93 Ranger uses a Speed Sensor in the tail of the Transmission/Transfer Case to read the Output shaft speed. A separate (ABS sensor) was used on the rear differential to read axle speed for the braking system. Wouldn't the ratio affect the speedometer accuracy due to it changing the Output shaft speed by speeding up, or slowing it down, at a given axle speed?
Lead Driver
Joined: Jun 2003
Posts: 8,298
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From: Damon (South East Texas)
My bad! I misread that. I swear I read it was a '93 this morning. But, it makes sense. No 5 speed auto in a '93. Also, Rich mentioned something about pre-OBDII and I got thrown off. 
Hotshot
Joined: Nov 2006
Posts: 11,286
Likes: 263
From: North of Greenville
Wow... I just read this for the first time and saw the '03 in the OP's first post, and I have to admit that I was beginning to think a few bats had flown out of y'all's belfry when you were talking about pre-OBDII kinds of issues.
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Lead Driver
Joined: Feb 2000
Posts: 5,373
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From: Palm Bay, Florida
WOW!!!! Thanks everyone, espessely MARK!! So, IF I were to say find a whole rear end (drum to drum) and swap it in with the 3.55.1 gears it would be a plug and play?
I'd REALLY LOVE to find one with DISC brakes too!
I'd REALLY LOVE to find one with DISC brakes too!