4406 Gear calculation

[Trolling]

Hi!

Does anybody here know if I should change the gear on the vss on my 4406?

It has a 19 tooth gear installed on it and I have stock size tires with no plans of up-sizing anytime soon.

The gps speed accuracy test will be done tomorrow and i'll bump this up again by then.

TIA,
-Carl

 

[ranger-93]

No need to change anything if everything is stock. only reason to change the speed sensor is if you changed gear ratios but assuming you have stock tires im guessing you didnt change gears. correct?

 

[Trolling]

nope, i didn't change any gears. I still have the stock 3.73's and went back to stock/oem tire size.

It popped in my head that the speedo was probably wrong due to the new transfer case since it went up to speed quicker than before, as in the truck was accelerating faster, but I still have to confirm that it is still within spec.

 

[Trolling]

So I went out and did the speed accuracy test via my gps. It looks like the speed indicated on the speedometer is 7.5mph faster than the vehicles actual speed.

based on a formula found here in the forum: (current vss gear teeth X Speed displayed on speedo) / Vehicle's Actual Speed

Based on that: (19 X 57.5) / 50 = 21.85

So, I need a 22 tooth vss gear right?

Are the gears available at the stealership?

 

[Trolling]

I just saw this thread/sticky with this information:

looks like it goes up to 21 teeth. anybody have the part number for a 22 teeth gear or should i just stick with 21?

 

[Trolling]

Bump!

Called up Ford ceritos, Ken Grody Ford, McCoy Mills Ford and Ford of Anaheim and none of them have the speedo gears and none of them found it in their system. And that took me almost 2 hours holding and patiently describing what a speedo gear is

I might resolve to buying it elsewhere but i'm still curious if a 21 tooth gear would suffice for my stock setup.

 

[ranger-93]

why dont you just remember that the speed is off? aint broke dont fix it?

 

[Trolling]

why dont you just remember that the speed is off? aint broke dont fix it?

lol.. that made my night

no.. I don't leave things incomplete, in this case an uncalibrated speed gauge.

 

[gijoecam]

Go with the 21 tooth. That should put you within a mph or so. Close enough for government work.

Also, did you verify that the speedometer is actually incorrect? i.e. is the needle off and displaying incorrect while the odometer is correct? Simple check: Find a flat, straight piece of freeway. Stop at a mileage marker. Reset the odometer and drive 10 mile markers. The odometer should also read 10. If you're setup is actually off the way your speedo indicates, you should read about 11.5 (assuming it's off by 15% like the speedo).

If the odometer reads correct, I wouldn't mess with the gear.

 

[Trolling]

Go with the 21 tooth. That should put you within a mph or so. Close enough for government work.

Also, did you verify that the speedometer is actually incorrect? i.e. is the needle off and displaying incorrect while the odometer is correct? Simple check: Find a flat, straight piece of freeway. Stop at a mileage marker. Reset the odometer and drive 10 mile markers. The odometer should also read 10. If you're setup is actually off the way your speedo indicates, you should read about 11.5 (assuming it's off by 15% like the speedo).

If the odometer reads correct, I wouldn't mess with the gear.

I found a place that had a 21 tooth gear. picked it up for $8

Yes, the speedo is actually incorrect along with the odometer.

 

[Trolling]

update;

installed red 21 tooth gear and the speed is still a solid 3.5-4mph faster compared to the GPS.

I might try out a 23 tooth gear soon.

Anybody have the same setup (stock + 4406) that has 23 teeth gears in their vss?