In the Gear Thread sticky, ( https://mustangboards.com/general-te...ar-thread.html ) MattJ included a Gear Ratio Calculator in his posting. I went to use it, but it doesn't have (as far as I can tell at least) a listing for the 2005 GT. Which of the ones available should I use to most closely match mine?

 

You have a 3650 in your 05

 

Thanks Matt. Do you know it that's really accurate?

I just went out and wrote down the MPH and the corresponding RPM's in 5th gear for 45MPH = 1,400RPM -- 50MPH = 1,500RPM -- 60MPH = 1,750RPM -- 65MPH = 1,900 RPM

Then I did same for 40MPH and 50MPH in 3rd gear and the RPM's were 1,750 and 1,900 respectively.

But according to that calculator and the trans you said to use, it's giving me these results:

5th Gear:
1,400 RPM - It says I'm going 51.5MPH
1,500 RPM - It says I'm going 55MPH
1,750 RPM - It says I'm going 64MPH
1,900 RPM - It says I'm going 68MPH


The 3rd gear ones were this;

1,400 RPM - It says 24.5MPH
1,900 RPM - It says 33MPH

 

do you have an 05 GT automatic or stick? because the automatics are geared at 3.31 and the stick has 3.55s.