How to: Speedometer Gear Color Code Specification Chart With Formulas, And Ford Part Numbers.

[Naasau]

Good answer... I have always wanted a second X with 2 doors as a dd, that I could make into a gas sipper.... a 2 wheel drive version would help with that. Though I've never thought of it before.

 

[chevyflyfisher]

what sensor kit is this

Here is a vehicle speed sensor (VSS) with the speedometer gear on the bottom. The metal bracket in the center is the piece that holds it down. The one pictured is for older vehicles without any electrical connector. Newer vehicles have a 2 pin electrical connector. That is what sends the signal to the PCM. The later model vehicles don't use this at all (98, and above). They get their signal from the sensor on the differential.

Vehicle Speed Sensor Kit.
This kit enables a 4L60E transmission (electronically controlled 700R4) to read vehicle speed in order to calculate when to shift. Use of this kit allows you to retain the mechanical speedometer in your early model car or street rod. This kit is an upgrade from the older sensors.

Here is an ABS speed sensor:

Notice the resemblance between this sensor, and the one in the picture above. Both have no gear on the end.

i have a 92 silverado i just bought. i was told that the transmission was replaced. i have no speedometer. this kit in the picture looks like the one on the transmission. i know that my truck is set up for electronis vss. how do i get it back?

 

[chevyflyfisher]

i have two wires that have been clipped from the factory set up. can i take this sensor out and go back to the stock sensor?

 

[BrooklynBay]

Do you know which sensor it previously had? This is a gear driven VSS. The newer vehicles use a different sensor on the differential which has no moving parts.

 

[CobraTrans]

Very very interesting thread, thanks everybody!!!

 

[chevyflyfisher]

the transmission was rebuilt before i bought it so i don't know what it came out of. but now i have a gear driven vss and a truck (92 2wd silverado) that's set up for electronic vss. My guess is that I'll probably just run a cable and autometer to the gear driven sensor thats on the transmission and just mount a new gauge on the dash. i don't know how far i want to get into this truck? if i want to break it down and put new gears in it or not?

 

[alfilrey]

Very interesting this thread, I added it to my portfolio, I have a 91 FORD EXPLORER that was at its best years Eddie Bauer, today is a style PreRunner slightly changed.

 

[andrewgordon]

speedo gear keeps stripping

Hi People, I have read all the posts in this thread with great interest, however nothing seems to mention the problem I have. My 97 V6 manual Explorer had a 19 tooth speedo driven gear when I bought it, gear in pefect condition but not reading accurately. I fitted a genuine ford yellow 18 tooth gear and speedo became very accurate, but after about 1000 km gear is chewed up and stops reading. original and replacement gear are rh twist, I have tried 2 new gears now, and both times worn out after about 1000 to 1500 km. Any suggestions?

 

[Naasau]

I hate to ask, but have you pulled the transfer case apart to look at the drive gear?

 

[andrewgordon]

I had the transfer case apart a few months ago and while I was not looking for a problem with the gear specifically, I did inspect all components before re-assembly. Part of my confusion is that the original 19 tooth gear performs fine but the 18 tooth gear keeps wearing out, diameters are both the same but it only wears the slightest amount off the tips of the teeth and allows it to slip.

 

[mr cribb]

I'm having an issue trying to figure out my thought....

my overall plan is a s/c 4.0, backed to M5OD... and THINKING about 3.08 gears for fuel economy (I currently have 3.27 gears).

Every calculator I tried I can't get anything close to what I see above for speedo cable gear.

Mine is 2wd.

 

[Maniak]

Personally, I wouldn't even think of going lower than 3.27. While it will lower your highway RPMs you may not have enough motor to maintain speed. You may even be lugging the motor at that low of an rpm (assuming you leave it in top gear on the freeway) which will lower your mileage.

Assuming you are going to go with a 3.08 you really need to find out how many teeth you have now with your 3.27 gears. Just pull the speedo cable out of the transmission and look at the gear. Most of the ones I have seen have a # right on them but worst case you just count the teeth. Once you have that you can do some simple math and see if what size gear to buy that will be is 6% bigger. That is assuming they even make a gear that size.

~Mark

 

[andrewgordon]

Finally sorted out my speedo issue, used a borescope and found that the speedo drive gear in the transfer case was stripped, just as Naasau suggested. Fitted a new gear today and now have a steady speedo and cruise control. Now to wait and see if it also helps with the intermittent engine miss.

 

[mr cribb]

When all is said and done, I will be running a set of 31 10.50's. This is the max tire size I can run on my current 3.73's. I don't feel like new gears for the axle, and 31's are reasonably affordable if one fails on me.


So by my calculations, and I hate math, it looks like I will need a 16 tooth gear when I get my new tires.

I figured:

31 x 10.50 15 is a 30.7 inches tall multiply that by 65 for speedo reading divided by old tire size of 235/75/15 is 28.5 inches tall.

the equation looks like this:

30.7 x 65 / 28.5 = 70 mph actual travel speed

now current speedo gear is a 17 teeth white.

17 x 65 / 70 = 15.7857142857 round this up to 16 since a 15 teeth gear isn't made.

Is this correct?

 

[rdljpl]

Stock 89 Ranger

I have read all of the Speedo posts and am very confused! When my stock 89 Ranger's Manual 5 speed Transmission failed I bought a rebuilt replacement 5 speed.

Installed it and now my speedo reads at least 20 mph high. According to what I read here with my stock wheels and tires and 3.57 gears, I need a 19 tooth PINK Gear.

Am I close?

 

[rdljpl]

92 stock Ranger

I just have one more question before I slide under the PU. is it possible to just remove the cable from the sender and not pull the whole unit, because I wonder if got a transmission with the wrong internal gear or one with the wrong external gear. If we got a transmission with the wrong internal gear it will mean that I will have to do much more work under the PU and I am too old to keep getting up from the creeper.