How to- 95 96 97 Ranger Speedometer Calibration for Cheap

...Before I did my gear change on my 95 Ranger, I had kept reading for the 95 and newer Rangers how you needed an electronic device to dial in your speedometer or where you had to take your vehicle into a shop and have them plug into your computer to change the values for the speedometer calibration to work..

..I am happy to say that this is not the case...:biggthump

..The Story

..When I first got my truck it had 30" or 31" tires on it with stock 4.10 gears and I quickly moved up to 32" tires while working on horsepower upgrades to push the bigger tires over the past number of years..

..In the meantime I started doing speed control with my on board GPS and found it very accurate for what I needed and I learned my speedo was off (reading slower than actual speed) about 5-7 mph progressively between 50 and 70 mph..(actual 55-77 mph)

..The need for more power recently lead me to 4:88 gears as an upgrade for the 32" tires..I thought before the gear change and quickly confirmed afterward that the RPM's would be running a tad bit high in all gear ranges..With this set-up my speedo was reading 5-7 mph faster than I was actually going in all gears over 20 mph according to many miles watching the GPS..

..Along come the 33" tires to settle the 4.88's new high RPM's down a little bit and to see what a difference this would make on the speedometer reading.. I got the speedometer down a little bit to about 4-6 mph progressively in all gears over about 30mph..

...Needless to say this became a little confusing trying to keep up with my current math equations while out of town and coming up on a known speed trap....
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..It was time to calibrate my Speedo..

..I knew that the older vehicles had a gear at the end of the speedometer cable plugged into the trans (auto/manual trans) or transfer case (4x4) while the 95 and newer Rangers were to use an electronic speed sensor on top of the rear axle to get the speed readings from..

..Now that I got the tire and gear ratio I wanted I decided to crawl under the truck and do some investigating...Just my luck, an electrical connector..


..So I decided to unplug it and pull it out..(7/16 socket or metric equivalent.. )


..When I pulled it out I was surprised and excited to find it had a plastic gear on the end and I remember reading up about them in this thread..
http://www.explorer4x4.com/speedo.html



..After going back and re-reading that thread now that I know I have a plastic gear I can swap out, I took special note of this information..

..With all the "Simple Gear Calculators" out there, this info helped me the best..

I told Gene that I had a 19-tooth speedo gear. He didn’t ask what vehicle or gear ratio or even tire size that I had. I then told Gene that when my speedometer was reading 70 MPH I was actually going 65 MPH.

This one was very easy for Gene. He said that to slow down the speedometer 5 MPH we wanted to add one tooth to the gear. Very simple.

Click to expand...

..Now I'm excited..

..I probably have a 19 tooth gear and all I have to do is count the teeth and verify the color of the plastic gear...I quickly ran over to read this thread before I started counting teeth on my gear.

..The Speedometer gears and color code chart..
http://www.explorerforum.com/forums/showthread.php?t=158739&highlight=gear

..Piece of cake..16-21 tooth gears and all I need to do is add 1 more tooth to my plastic gear and I'm set...(List price $18) Let's give this a count...


..Wait a minute...My plastic gear is RED and I confirmed the tooth count as being 21....There's got to be one with 22 teeth...

There is not a 22 tooth gear for this..:thumbdwn:..In fact, Ford makes up to 26 tooth gears for other vehicles but for this gear configuration they stopped using the 22 tooth gear back in the early 60's due to failures since the teeth were so thin..

..But what am I gonna do?

..So I started calling Speedo shops and Pro Street shops and after several failed attempts of finding either a 22 or 23 tooth gear at these places, I was on my own to search the net..

..I kept coming up with the same thing and every 23 tooth gear I read about was a GM product of a different configuration until...

..Until I stumbled upon and read this info on a Full Size Bronco..:biggthump
http://bronco.zenseeker.net/Speedo.htm

...He had all the gears and the numbers of the 16-21 tooth gears also but wait, what was this?..It's a 23 tooth gear that looks just like ours...But could it be?..Would it work?

..It's a Jeep part..P/N J3167393 =$10



..And it is a white gear not to be confused with the Ford white gears and their tooth counts...


..The Outcome

..While I thought the 22 tooth was the fix this is as close to probably what the stock speedometer reading was...

..My speedometer now reads about 2 to 2-1/2mph over my actual speed thru all of the gears and dead on 90% the rest of the time..(with the 23 tooth gear, 4:88 gears, and 33' BFG tires)

..Meaning that it's pretty dead on for a manual trans and if it's off it's in my favor..
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Added Bonus - Parts and Part numbers

..All of the items (separate) that comprise this sensor set up..


..Installed together..


..Some info

..I wanted a new "O" ring for my sensor as mine had shrunk a little and was getting hard..Ford does not sell the "O" ring by itself and it only comes from them attached to the sensor...

..The sensor P/N from Ford is E9LZ-9E731-A while it's Alternate number (while still a Motorcraft number) used by Ford and many aftermarket suppliers is DY-588 -List Price = $39.80

This part can be found on over 1000 different models of Ford/Lincoln/Mercury and from what I could find from years 1984-2004..


..If you do buy a 16-21 tooth gear from Ford it does not come with the "C" clip..This is sold separate..P/N C1DZ-17292-A = List -$1.78


..I hope this will help you out on your next project..

..Just for fun I pulled the gear out to see how the Jeep part likes it's new home..

..Apparently the Jeep gear is a hair fatter than stock so it did it's own self clearancing..I was warned to buy 2 on anything bigger than a 21 tooth gear but it looks like it's gonna work..

'98-'11 Rangers are the ones you need the electronic programmer for.

FWIW, you can change the drive gear that's inside your t-case from the 7-tooth gear to the 6-tooth one. This should allow you to use a 19T or 20T speedo gear having thicker teeth. Of course this would require you to crack open your t-case.

Of course this would require you to crack open your t-case.

Click to expand...

..There's only one reason I'm cracking open this case and it ain't got nothing to do with that 6 or 7 tooth drive gear..

..But true, there are other options..I was looking for easy and cheap..:biggthump

...Update..

..I've been driving the snot out of the Ranger and this speedo calibration fix is working like a charm...:biggthump

I just wish there was a 22 tooth gear

..Why don't you give the 23 tooth gear a try?..

..All the calculations I kept coming up with using the various calculators were confusing at best for my truck...The gear is cheap and it's a few minute swap..

Every time I have done the calculations, selected a gear and installed it I got precisely what I expected from my calculations. It's part of what I do as a mechanical and systems engineer. I don't even use the various calculators on line, I just create the formulas in Excel. You kow the thread, you offered me a 21 gear on that thread. I should probably take you up on that. Here it is.

I was considering going with the 21 or the 23. The 23 would be closer (% or error wise) to correct especially at higher speeds. The 21 has the appeal that it should lessen the shifting issues I believe I am having due to the VSS being off without going the other direction.

I will probably order both and experiment. Unfortunately I don't know if I can change this gear without dropping the tank. The combination of the large V8 tank and the 4406 doesn't leave much room. Jim had left a chunk of the original plastic tank protection that was hard wedged between the VSS and the tank. I removed it when I dropped the tank to find out what gear I had in there (20 tooth). Removing that left a bit of room, but I am not sure if it is enough to remove and replace the VSS.

..Did the 23 tooth gear resolve this for you?

The 23 tooth did exactly what I thought it would. The percentage changed as I expected. FYI you can remove the speed sensor without dropping the tank. You can't see what you are doing, but it can be done.

About a thousand miles after I replaced the gear I lost my speedometer altogether. I do not beleive it was directly related to the gear change. I am thinking it is either a short/open wire or the computer. I just stumbled across some testing perameters that I can check and I may do that later today.

Does changing the vehicle speed sensor gear size require changing the one inside?

I swapped the transfer case in my 1996 ranger for a used one. Now my speedo is off and the abs isn't working. If I swap the gear on the end of the vss do I need to change the one inside the transfer case or will that great accommodate a range of different teeth counts? Your input is greatly appreciated!

If your location was under your name I might be able to give an educated huess on your brake problem. .

The first link in the first post has the plastic gear options which would help. The big gear rarely ever needs changed except rare situations....

Did you change tires? There are i think two commonly used big gears in our transfer cases bur without knowing your tiresize axle gears and what color plastic speedo gear you have makes it tough to answer.

From your description I'm not sure..

I'm in Madison Wisconsin. So, you're saying that I can put the red 21 tooth gear from the old transfer case's speed sensor if the gear in the current case is spinning a 19 or 23 tooth(not sure as I haven't taken it out) vss gear?

Thanks!

I don't know the gear ratio I'm running. Everything was fine with the old case before it failed. After the case was swapped, there's a problem with speedometer and abs.

That plastic gear can be changed between the two but the big gear is more of a tc project. If it worked with one it will work with the other.

It only takes a lil bit of mud in front of a sensor and its off unless I'm missinv something.

Maybe someone else can chime in.

The sensor is functioning. It's just spinning at the wrong speed. TBars, I see you mentioned that you swapped the gear. So, you changed the tooth count on the sensor, but left the one inside the case and had no problems? My engineer buddy said that when the tooth count changes, the drive gear needs to change also because the size or tooth pitch will change.

Thanks for your help!

So, I just took the vss out and swapped the 18 tooth yellow gear with the 21 tooth red one from the sensor in the broken transfer case. Apparently the internal gear works for both. My speedometer is accurate above 50 mph and a couple mph off at lower speeds. It turns out I also had a bad connection at my right front abs sensor. No abs light! Thanks Tbars4!

Glad to hear you got it all worked out..:biggthump