So everyone here knows I'm running 40in tires with 3.55 gears. If I remember correctly it's 10MPH slower t(just got back from training so I can't remember)what it actually is. So if it says I'm going 50 I'm actually going 40. Called transmission center (HeyYou advised it) and here is what they told me. I would need a 23 tooth gear but Didn't only made a 26 tooth gear which would make my speedo 10MPH off. He recommended this product which speeds up my speedo. Now I'm going to verify how much it is off, but figured I would put this out there for anybody in the same boat as me

 

Huh? That doesn't seem quite right.... 10mph off at what speed? Your speedometer will be off by a percentage of actual speed. I fail to see how three teeth is going to make a 10 mph difference. Maybe at 150mph or so......

Nice to see ya back.

 

Its off 10MPH from 15 to 75 I don't know what teeth gear I have now. Just wish I could buy a tuner like I can for my 01

 

Not possible. It's a mathematical relationship between gear ratio, tire size, and tooth count on the drive/driven gears for the VSS. It is not a linear relationship. It will be off by a percentage of your speed regardless of how fast you are going. If you are 10% off, at an indicate 10, you are actually doing 11. At an indicated 60mph, you are actually doing 66, etc. It isn't a fixed amount over some speed range, that simply isn't possible.

 

according to my GPS it is :b

 

Then your speedo is screwed up.

 

I don't see how since it's just a cable :b I'm just trying to get it right while I have down time. I'm driving my new Power Wagon

 

Cable? Should be electronic.......

 

What percentage did you get? They have from 11% and different percentages up to 100% I'm assuming the guy from PATC told you what you would need.

 

What truck is this on? What trans? What year electronics?