chavalo_nm1

I have recently got 4.10 gears and a TLOK in...........when I put in 4.10 gears as the gear ratio..........it really went screwed up. The speedo shows like 25 mph higher than it should be. I had to put in a 4.56 gear ratio to get it closest that i could which is still 10/15 miles off. Am I doing something wrong guys?
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68XR7

You didn't say whether you were using a custom tune or not. When I had my 3:73's put in, the service manager told me that he couldn't calibrate my speedo for the new gears because Ford never offered my car with the 3:73 ratio. He said that he had no way to adjust it to work properly. He fooled around with the tire size, just trying to get it a little closer, but it was still way off. The problem was easily fixed by programing the new ratio into my xcal2. But as far as my stock tune is concerned, no luck.

Trmachuno

That's weird. Even before I fixed my speedo from my 4.10's w/the tuner, my speedo was only 20-25mph overand you say w/the correct calibration, they are still that much over? Make sure they're 4.10's. Check the brand, box, and check your tuner and try recalibrating it to 4.10 gear ratio again. Good Luck with this.

chavalo_nm1

hmmm........I tried the 4.10 option again and it got worse............it seems that the lower I go on the ratios.....the more off the speedo gets........the tune I have on there is dougs race tune. can anyone chime in?

banka87

Do you still have the stock rims and tires?

Trmachuno

Good idea! I didn't even think about it. Did you tell doug all the following when he was making the tune:
-4.10 gear ratio
-size of tires and rims or revolution per miles of your tires(calculated through some equation)
-Any other mods you forgot to tell him about when making the tune?
It's gotta be tires, rims, or gears. That's the logical explanation.

rmays06

I had to have my tune fixed, the car ran about 20 MPH higher when I put the 3.73's in, adjusted the tune and bingo all better. From what I hear there is no way to adjust them without the tune. The tire will play a llil roll in it but stock they are 27" so are you willing to go to a 25" tall tire rim combo to adjust it?

chavalo_nm1

im gonna try and giving doug a ring.......like rmays says............maybe its in the tune.

Sancho805

yes.....doug is your solution.

rmays06

It'll work he does wonderous thing with that tuner....Make sure he know about the gears.