? 4 Mike Speedo Correction
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From: Nor-Cal,USA
? 4 Mike Speedo Correction
Hey Mike I know this may not be the correct forum but I figure you are the best person to ask. I own a 97 F150 4x4 5.4 E4OD tranny that I am going to be lifting within the next few weeks and I am taking it in on Monday for new ring and pinions Front and Rear. Going to 4.56's and will then be adding 35x12.50x18 BFG Mud Terrain tires. I also happend to get in on the group buy on FTW for the NEW 1715 and would like to know what I am going to have to do to make my speedometer read correctly once I have everything complete and then use the Programmer to help up the HP output? I know the Programmer does not work to correct the speedo on my model year but what does and what do I ned to get to correct the speedo and make it accurate?
Thanks,
Richard Dean
Thanks,
Richard Dean
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From: Nor-Cal,USA
Very Carefully.
OK Mike I have learned that i need to replace my VSS gear which is located on/in the transfer case on my truck however I do not know what gear tooth I need to use to correct the speedo would you happen to have this info based on what i have told you I am doing to the truck and if so where i can get one of these VSS gears?
Richard
OK Mike I have learned that i need to replace my VSS gear which is located on/in the transfer case on my truck however I do not know what gear tooth I need to use to correct the speedo would you happen to have this info based on what i have told you I am doing to the truck and if so where i can get one of these VSS gears?
Richard
Last edited by Richard D; Aug 24, 2003 at 05:56 PM.
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Joined: Mar 1998
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From: Virginia
Hi Richard,
You get the gear at any Ford parts counter, for well under $20.
No, there is nowhere near enough info in your post for me to tell you how many teeth you'll need on the new gear. Nor do I do that for everyone individually - instead, and this is far better for you, I have posted the info on how anyone can easily calculate that for themselves - I've posted that info a number of times right here in this section, for everyone to use.
So to determine the number of teeth you'll need on the new gear, use the search feature to pull up any of my posts over the years where I've gone over exactly how to do the math to determine the number of teeth needed on the new gear- that info has been posted here any number of times in this section by me previously, so it should be easy to find. It tells you what info you'll need from your vehicle and how to do the very simple calculations.
The easiest way (there are a number of ways, this is just an easy one) is to see what your speedo indicates (this is once the 35's & 4.56's are both installed, of course) at a true road speed of 50 mph. Whatever error there is at 50 mph, double that number and that will give you the *percentage* (%) of speedo error. You then apply that percentage to the number of teeth on your present speedo gear to get the number of teeth needed on the new gear, voilą! Pretty simple.
In this case you've got both a tire size *and* a gear ratio change to deal with, so you will have to install both the taller tires and the gears and *then* find out how far the speedo is off *before* you can determine the number of teeth you'll need on the new speedo gear.
If we had *only* the gear ratio change, then we could tell you the number of teeth needed by knowing the number of teeth on the present speedo gear, and the before & after gear ratios. But because both tires *and* gears are being changed, you will need to install both and then see how far the speedo is off before you can determine the number of teeth needed on the new speedo gear.
By the way, this is something that any speedo shop can easily handle for you if you like, as speedo gears are how speedos were calibrated for *decades*, so this is a very simple job for any speedo shop in case you don't want to do it yourself. You can roll it in with the gears & tires installed, and 30 minutes later they'll have it tested & recalibrated for you.
Good luck!
You get the gear at any Ford parts counter, for well under $20.
No, there is nowhere near enough info in your post for me to tell you how many teeth you'll need on the new gear. Nor do I do that for everyone individually - instead, and this is far better for you, I have posted the info on how anyone can easily calculate that for themselves - I've posted that info a number of times right here in this section, for everyone to use.
So to determine the number of teeth you'll need on the new gear, use the search feature to pull up any of my posts over the years where I've gone over exactly how to do the math to determine the number of teeth needed on the new gear- that info has been posted here any number of times in this section by me previously, so it should be easy to find. It tells you what info you'll need from your vehicle and how to do the very simple calculations.
The easiest way (there are a number of ways, this is just an easy one) is to see what your speedo indicates (this is once the 35's & 4.56's are both installed, of course) at a true road speed of 50 mph. Whatever error there is at 50 mph, double that number and that will give you the *percentage* (%) of speedo error. You then apply that percentage to the number of teeth on your present speedo gear to get the number of teeth needed on the new gear, voilą! Pretty simple.
In this case you've got both a tire size *and* a gear ratio change to deal with, so you will have to install both the taller tires and the gears and *then* find out how far the speedo is off *before* you can determine the number of teeth you'll need on the new speedo gear.
If we had *only* the gear ratio change, then we could tell you the number of teeth needed by knowing the number of teeth on the present speedo gear, and the before & after gear ratios. But because both tires *and* gears are being changed, you will need to install both and then see how far the speedo is off before you can determine the number of teeth needed on the new speedo gear.
By the way, this is something that any speedo shop can easily handle for you if you like, as speedo gears are how speedos were calibrated for *decades*, so this is a very simple job for any speedo shop in case you don't want to do it yourself. You can roll it in with the gears & tires installed, and 30 minutes later they'll have it tested & recalibrated for you.
Good luck!
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Senior Member
Joined: Dec 1969
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From: Nor-Cal,USA
Thanks as usaul Mike not sure what other info you needed but here is all I know. Stock gears are 3.55 stock tires were 265/70/17 but I switched teyose out to 285/75/16 and I think my speedo is even off now. New gears will be 4.56 and teh new tires will be 35x12.50x18. Anyway I have already tried for and they only show one gear for my truck. I was however lucky enough when I dropped my truck off today to get the name and number of a place that is about 1.5 hours drive for me to at least get teh help I need and hopefully get it just right.
Thanks again for your help MASTER!
Richard
Thanks again for your help MASTER!
Richard
Former Sponsor
Joined: Mar 1998
Posts: 13,385
Likes: 4
From: Virginia
Hi Richard,
If you run into trouble finding a selection of speedo gears for your 1997 E4OD, you can try talking with some of the transmission shops in your area & see if they can help you source, and worst case, if all else fails, a speedo calibration shop should easily be able to supply whatever is needed.
If you run into trouble finding a selection of speedo gears for your 1997 E4OD, you can try talking with some of the transmission shops in your area & see if they can help you source, and worst case, if all else fails, a speedo calibration shop should easily be able to supply whatever is needed.