Notices
Pre-Power Stroke Diesel (7.3L IDI & 6.9L) Diesel Topics Only

speedometer off

Old Aug 8, 2014 | 06:18 PM
  #1  
brokeasajoke's Avatar
brokeasajoke
Thread Starter
|
More Turbo
15 Year Member
Liked
Joined: Jan 2010
Posts: 685
Likes: 1
From: Western NC mountains
speedometer off

So using my gps my speedo reads ~5mph fast. Mine is driven off of tcase. Dont remember gear color or teeth count. 235s 4:10 zf5. Can i change just gear on cable end or do i have to change worm drive gear?
 
Reply
Old Aug 8, 2014 | 10:00 PM
  #2  
hairyboxnoogle's Avatar
hairyboxnoogle
Lead Driver
Joined: Apr 2008
Posts: 6,945
Likes: 13
Seems about par for the course on OBS trucks. My 92 is fast and so is our 97.
 
Reply
Old Aug 8, 2014 | 11:21 PM
  #3  
Red454sedgwick's Avatar
Red454sedgwick
Posting Guru
Joined: Feb 2013
Posts: 1,203
Likes: 0
I put bigger tires on and it was right. I don't think you have to change the worm gear I did a 4.10 and 3.55 a couple years ago and they had the same worm gear it's either brown or yellow the gears are color coded
 
Reply
Old Aug 8, 2014 | 11:23 PM
  #4  
Red454sedgwick's Avatar
Red454sedgwick
Posting Guru
Joined: Feb 2013
Posts: 1,203
Likes: 0
Originally Posted by hairyboxnoogle
Seems about par for the course on OBS trucks. My 92 is fast and so is our 97.
with the digital speedo there is suppose to be an dial on the back of the instrument cluster, but I've never cared enough to look.
 
Reply
Old Aug 9, 2014 | 04:01 AM
  #5  
tjc transport's Avatar
tjc transport
i ain't rite
Joined: Mar 2005
Posts: 65,548
Likes: 5,589
From: Marlboro Mental Hospital.
Club FTE Gold Member
Originally Posted by Red454sedgwick
I put bigger tires on and it was right. I don't think you have to change the worm gear I did a 4.10 and 3.55 a couple years ago and they had the same worm gear it's either brown or yellow the gears are color coded

yup, all you need to change is the cable gear . i have used red,yellow, green and white gears in my 88. 1 tooth is good for about a 2.5 mph change in speedo reading.
 
Reply
Old Aug 10, 2014 | 06:12 PM
  #6  
speedwrench72's Avatar
speedwrench72
Posting Guru
Joined: Dec 2012
Posts: 1,065
Likes: 2
From: western washington
I believe on digital dash you have to flash the PSOM. on trans with vss in the trans 92 and earlier you just change gear, there are two output shaft worm gear ratios, should be ok.
 
Reply
Old Aug 10, 2014 | 06:25 PM
  #7  
tjc transport's Avatar
tjc transport
i ain't rite
Joined: Mar 2005
Posts: 65,548
Likes: 5,589
From: Marlboro Mental Hospital.
Club FTE Gold Member
pre 91 is simply changing the gear on the cable, 92 and newer is electronic and reads off the VSS in the rear differential.
 
Reply
Old Aug 10, 2014 | 07:00 PM
  #8  
speedwrench72's Avatar
speedwrench72
Posting Guru
Joined: Dec 2012
Posts: 1,065
Likes: 2
From: western washington
the cable and gear are for the speedometer and odometer, the vss converts information to electrical signals for the E4OD PCM, ALL VEHICALS with E4OD have a vss on tranny or when they went digital used the same sensor for anti lock, speedometer, cruse control, and tranny in latter models mounted in rear-end. not all vehicles, or drivetrain combinations that ford produced went digital at the same time.
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Every 2026 Ford Engine Explained

 Brett Foote
story-1

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-2

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-3

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

 Verdad Gallardo
story-4

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

 Joe Kucinski
story-5

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

 Brett Foote
story-6

Top 10 Ford Truck Tragedies

 Joe Kucinski
story-7

AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

 Brett Foote
story-8

Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

 Michael S. Palmer
story-9

Ford's 2001 Explorer Sportsman Concept Looks For a New Home

 Verdad Gallardo
Old Aug 11, 2014 | 12:12 AM
  #9  
BruteFord's Avatar
BruteFord
Postmaster
Joined: Mar 2013
Posts: 3,066
Likes: 7
From: Over There
Originally Posted by brokeasajoke
.... my speedo reads ~5mph fast.....
Originally Posted by tjc transport
...... 1 tooth is good for about a 2.5 mph change in speedo reading.
Cause speedo calibration is a math thing I need to point out that these statements don't give enough information. Speedo correction is a matter of percentages or ratios, so "5 mph fast" or "2.5 mph change" also need to know at what speed so a percentage or ratio can be found. For example if it's reading 5 mph fast when you're going 50, then it's 5/50 or 10% off, but if it's reading 5 mph fast when you're going 25 then it's 5/25 or 20% off.
 
Reply
Old Aug 11, 2014 | 05:01 AM
  #10  
tjc transport's Avatar
tjc transport
i ain't rite
Joined: Mar 2005
Posts: 65,548
Likes: 5,589
From: Marlboro Mental Hospital.
Club FTE Gold Member
Originally Posted by speedwrench72
the cable and gear are for the speedometer and odometer, the vss converts information to electrical signals for the E4OD PCM, ALL VEHICALS with E4OD have a vss on tranny or when they went digital used the same sensor for anti lock, speedometer, cruse control, and tranny in latter models mounted in rear-end. not all vehicles, or drivetrain combinations that ford produced went digital at the same time.

once again.
SPEEDOMETER on vehicles 91 and older is gear driven.
SPEEDOMETER on vehicles 92 and newer is electronic and driven off the VSS is the rear differential.
we are not talking about ABS, trans signal, or cruise control signal.
if you disconnect the electrical sensor on a pre 91 vehicle with E4OD trans, the speedometer will still work, but the trans will go into limp home mode.
 
Reply
Old Aug 11, 2014 | 04:09 PM
  #11  
brokeasajoke's Avatar
brokeasajoke
Thread Starter
|
More Turbo
15 Year Member
Liked
Joined: Jan 2010
Posts: 685
Likes: 1
From: Western NC mountains
Cant really tell under 25 too much bounce. But seems 5 off everywhere respectively per gps +or- 1 mph to 55- 60 mph. Mine is an 88.
 
Reply
Old Aug 11, 2014 | 05:02 PM
  #12  
tjc transport's Avatar
tjc transport
i ain't rite
Joined: Mar 2005
Posts: 65,548
Likes: 5,589
From: Marlboro Mental Hospital.
Club FTE Gold Member
if you are off around 5 mph low at 55-60, i would drop 2 teeth size on the speedometer gear. this should get you in the ballpark.
this is what i had to do to get mine close.
 
Reply
Old Aug 11, 2014 | 06:10 PM
  #13  
brokeasajoke's Avatar
brokeasajoke
Thread Starter
|
More Turbo
15 Year Member
Liked
Joined: Jan 2010
Posts: 685
Likes: 1
From: Western NC mountains
Im reading 5 fast so i should go up 2 teeth correct? Which should turn cable slower.
 
Reply
Old Aug 12, 2014 | 04:55 PM
  #14  
tjc transport's Avatar
tjc transport
i ain't rite
Joined: Mar 2005
Posts: 65,548
Likes: 5,589
From: Marlboro Mental Hospital.
Club FTE Gold Member
correct...
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Aaron Keiser
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
8
Sep 30, 2018 10:28 PM
Hunt89
1987 - 1996 F150 & Larger F-Series Trucks
20
Apr 16, 2010 04:12 PM
cbfomoco
1967 - 1972 F-100 & Larger F-Series Trucks
5
Sep 23, 2008 03:10 PM
MikeGV
1987 - 1996 F150 & Larger F-Series Trucks
7
Sep 26, 2005 09:30 PM
nate5812
1973 - 1979 F-100 & Larger F-Series Trucks
5
Apr 15, 2005 04:02 PM


Thread Tools
Search this Thread

All times are GMT -5. The time now is 02:01 PM.

story-0
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-1
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-2
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-3
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-4
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-5
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-6
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE
story-7
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

And it might be even better than that.

By Brett Foote | 2026-05-18 19:26:42


VIEW MORE
story-8
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Slideshow: Does lowering an F-150 Lobo RUIN the ride quality?

By Michael S. Palmer | 2026-05-18 19:20:37


VIEW MORE
story-9
Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Slideshow: Ford's bizarre fishing-themed Explorer concept has resurfaced after spending decades largely forgotten.

By Verdad Gallardo | 2026-05-12 18:07:46


VIEW MORE