Does anyone know where i can find the final drive ratio for a 04 screw 5.4? I have 37"s and am getting 5.14s but i would like to know the final drive ratio so i know im making the right decision.

 

The lowest ratio you can get is 4.88 in the 9.75 and 8.8 reverse. So not sure what you are asking.

 

If you are using a gear/speed calculator, overdrive is 0.7:1. 3rd is 1:1. Transfer case ratio is 1:1 if you are in 2hi or 4hi.

http://www.4lo.com/calc/gearratio.htm

 

I never said i had a 9.75 or 8.8. Thanks GLC for the info. How did you come up with those numbers btw?

 

3rd gear in a 4R75E is 1:1 and 4th is 0.7:1. Transfer case in high range is direct drive.

A 04 5.4 Screw has a 9.75" rear and 8.8" reverse cut front if you have 4wd.

 

Thanks, i have decided on 5.14. I have a 9" rear end.

 

No, you have either a 8.8" or a 9.75" from the factory.

 

IF your truck is 4WD, 5.13 is not gonna fit in the front axle... its not even made for that reason. so if you wanna mix and match ratio's go ahead.

 

LOL you just dont get it, I dont have a factory rear end. And its not a 4WD. Thanks anyways.

 

Off topic but are you running disc's on your 9"? What'd it come out of as well? I'm putting a 9" in my explorer and made my own conversion kit using suzuki sami rotors, and olds bravada calipers. Have 5.14 and a full spool in it as well.
I'd like to upgrade my 05 f150 to a 9" too

 

Its a Dirt Tech full fabricated 9". I have one picture in my album. Running 14" disks.

 

5.14's might be alittle low for you.

what do you plan on doing with the truck? Looks like desert racing.

Ive got 5.13's runnin 40's but i just trail ride and mud bogs pretty slow stuff, that desert racing can be pretty quick cant it?

 

Good grief - you come in here and ask a question on how to find your final drive ratio - that kinda hints that you aren't that knowledgeable. How can we assume that you don't have the stock rear end in that thing? Thanks a pantload for not telling us up front that it ain't stock.

 

GLC: are those numbers the same for the 4r70w thats in my 99? If not then can you get mine?

thanks bud

and mines not stock either sorry man i had too

 

OP: thanks for specifying that little bit of info.

you will be fine w/ 37's and 5.14's. a buddy of mine had an F-250 w/ the 5.4 on 37's w/ 5.13's, and he did just fine offroad, and driving the truck daily.