vss drive gear

[Trolling]

is it possible to replace the drive gear on the transfer case shaft to correct the speedo after a 4406 swap?

i have the red drive gear (21 tooth) on the vss and the stock brown one on the 4406 and it reads about 4-5 mph over the true speed and that is the closest i can get it to since the red vss gear is the one with the highest number of teeth you can get without the risk of damaging the plastic gears. unless someone can find me one that has 22 teeth then that should put my speedo right on the dot. (<- that is assuming the calculator in this website is correct;http://www.cashandplay.net/CashandplayseBayGearCalculator.html; wherein my tire diameter is 28.077952755905514, my tc drive gear is 8 tooth and i have 3.73 diff gears)

so, i'm thinking of replacing the "other" gear to correct it. here's a pic of it just to be clear:

it should be an 8 teeth gear.

>>>

quick update: it looks like i need a 6 teeth drive gear (pink) to pair with the tan 19 teeth vss gear.

it's for a mustang and i don't know if it will work/fit in the 4406 drive shaft.

 

[gmanpaint]

Trying to figure this out is a pita sometimes. I feel your pain here, as I have been there a few times with all the changes in my rig. I have also asked and thought of having to change the t-case gear to correct the speedo, but in the end, it was just a simple VSS gear swap.

Have you tried to go to a lower tooth count VSS gear yet? There cheap and simple to replace. Replacing the ring gear will be a **** as you have to tear down the t-case to do so. Just a guess here but you might need to go lower tooth count like a 18-19 tooth gear. Each tooth is good for 2.5-5 mph diff.

Now since you have the 4406 t-case with a diff gear ratio, I am not sure about how it changes everything up, so I am tuning in here to see what you come up with.

Cheers to you and your quest.

 

[Trolling]

having the wrong gears seem to be messing with the shift points.

anyway, i used to have the tan 19 tooth gear installed there and the speedo read way too fast, fast as in i can hit 60mph at the speedo in 7 seconds fast. Then i bought a 20 tooth and 21 tooth gear and the red 21 tooth gear read the slowest/closest to true speed with about 4 mph over.

replacing the tc ring gear would just consist of removing the rear drive shaft and the rear tail-housing so it's not too difficult.

can anyone measure the brown drive gear that came with the 4406 transfer case? There's a pink one that's for a mustang with a top loader transmission that might fit if it has the same inner diameter.

 

[imp]

having the wrong gears seem to be messing with the shift points.

anyway, i used to have the tan 19 tooth gear installed there and the speedo read way too fast, fast as in i can hit 60mph at the speedo in 7 seconds fast. Then i bought a 20 tooth and 21 tooth gear and the red 21 tooth gear read the slowest/closest to true speed with about 4 mph over.

replacing the tc ring gear would just consist of removing the rear drive shaft and the rear tail-housing so it's not too difficult.

can anyone measure the brown drive gear that came with the 4406 transfer case? There's a pink one that's for a mustang with a top loader transmission that might fit if it has the same inner diameter.

BEWARE! The Ford Top-Loader has it's DRIVE GEAR pitch reversed from many others-- For exaple, B/W T-10. Reason is the opening in the tail housing is ABOVE the shaft in one, and BELOW the shaft in the other. imp

 

[Trolling]

BEWARE! The Ford Top-Loader has it's DRIVE GEAR pitch reversed from many others-- For exaple, B/W T-10. Reason is the opening in the tail housing is ABOVE the shaft in one, and BELOW the shaft in the other. imp

ahh, thanks imp! so does that mean the vss drive gear that those mustangs use have a different teeth direction?

the vss produces the same number of pulses/signal regardless of the direction the shaft/gear is rotated.

 

[imp]

ahh, thanks imp! so does that mean the vss drive gear that those mustangs use have a different teeth direction?

the vss produces the same number of pulses/signal regardless of the direction the shaft/gear is rotated.

As a matter of fact, the 2 DRIVE gears you have pictured above are NOT for the same transmission; look closely: the angle of direction of the teeth is opposite on one from the other. The lower pink one angles DOWNWARD from left to right; the other angles downward from RIGHT to LEFT. This means that if the wrong pitch direction DRIVEN gear is pushed into the hole, the teeth will be forced to conform the wrong way in order to mesh with the DRIVE gear. This will F.U. the teeth on the driven, but not usually the drive, gear.
imp

 

[Trolling]

As a matter of fact, the 2 DRIVE gears you have pictured above are NOT for the same transmission; look closely: the angle of direction of the teeth is opposite on one from the other. The lower pink one angles DOWNWARD from left to right; the other angles downward from RIGHT to LEFT. This means that if the wrong pitch direction DRIVEN gear is pushed into the hole, the teeth will be forced to conform the wrong way in order to mesh with the DRIVE gear. This will F.U. the teeth on the driven, but not usually the drive, gear.
imp

all that was pretty much self explanatory when you stated that the pitch is in a different direction.

what do you think about my previous question (post#5)?

so does that mean the vss drive gear that those mustangs use have a different teeth direction?

 

[imp]

is it possible to replace the drive gear on the transfer case shaft to correct the speedo after a 4406 swap? OK, let's start here. First, the DRIVE gear is ON THE OUTPUT SHAFT. The DRIVEN gear is the one on the VSS. So, yes, it's technically possible to change ANY gear combination if they are physically compatible with the output shaft diam., etc. Pitch must be compatible with EACH OTHER.

i have the red drive gear (21 tooth) on the vss and the stock brown one on the 4406 and it reads about 4-5 mph over the true speed....1. How do you know this? How do you know the true speed? 2. 4-5 mph over AT WHAT VEHICLE SPEED? Error in gear ratios exists as a PERCENTAGE of TRUE RATIO required. So, if TOO HIGH by 4 mph @ 50mph, it will indicate TOO HIGH by 8 mph @ 100 mph. So, IF it reads HIGH by 4 mph @ 50 mph, for example, the gear ratio is off by about 4 divided by 54, or 7.4%. If you cannot "dial-in" the correct gear ratio, you may put different tires on the vehicle which are BIGGER in diameter than your old ones by about 5%. In other words, for example, if your tires are now 28" in diameter, 29.4" tires will REDUCE the indicated speed by 5%.

I have not studied your source below. I do my own calculations, based on measured tire diameters, or the distance rolled per tire revolution. This is easiest for me.

Further info: Some transmissions/transfer cases have DRIVE gear teeth cut directly into the shaft, no replaceable gear. AOD automatics are typically thus. Ford has most often used 7, 8, or 9 tooth DRIVE gears, but certain transmissions were only supplied with 8 or 9, 7 not being available. The aftermarket has available ALL KINDS of gears, I should think you could buy the correct ones thusly. Sorry I'm avoiding talking about transfer cases; I don't have much experience with them. imp.......

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[Trolling]

1. How do you know this? How do you know the true speed?

GPS and a laser speed gun from a CHP i know. Both were consistent with their readings.

2. 4-5 mph over AT WHAT VEHICLE SPEED?

vehicle speedo read 30mph while true speed via GPS and laser read 26mph; speedo read 50 while GPS and laser captured/read 46; speedo read 70mph while GPS and laser captured 65mph. No tests done above 70mph per road speed limits.


But, none of these are of my concern. I'm more interested about this:

ahh, thanks imp! so does that mean the vss drive gear that those mustangs use have a different teeth direction?