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2003 5.4L Gear Swap from 3.73 to 4.56

Old 02-04-2011
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Question 2003 5.4L Gear Swap from 3.73 to 4.56

Okay so I am considering swapping gears in the f150 to give it a bit more punch off the line. It has stock 3.73 I was thinking about going to 4.10 or 4.30 gears. Right now the gears are very long in the truck. I'm still in second gear around 80mph. I only want to do this once, but I'm curious what it might do if I went to as high as a 4.56? Currently the truck cant even break the tires loose on dry pavement. I do have an edge programmer on it which has brought the truck to life. Also just did a tune up and its running better then ever, but some more oomph off the line would be nice.

Thoughts?

Last edited by Purplehazeir; 12-30-2011 at 08:48 PM.
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Old 02-04-2011
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Old 02-04-2011
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Only does me so good I have no clue what the transmission ratio is lol.
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Old 02-04-2011
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Figured it out. Looks like I may still go with 4.56 after all. At 70mph i'll be chilling at about 25-2600rpms which isn't bad. At 5k rpms in OD i can still go 140mph LOL
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Old 02-05-2011
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Yeah should be 1:1 in third and .70:1 in overdrive.

I've seen a vid of a supercharged 2wd f150 with 4.56 gears and the shifting seemed nice, but i have no clue what it's like on the highway. No matter what you do, second gear is just tall in these. Totally seems like they should have done the six speed a long time ago. lol
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Old 02-05-2011
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Go drive the truck on the highway with overdrive locked out, it's probably what the truck would feel like with 4.56 gears...? Check it with that calculator and try it out.
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Old 02-05-2011
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Originally Posted by Brian View Post
Yeah should be 1:1 in third and .70:1 in overdrive.

I've seen a vid of a supercharged 2wd f150 with 4.56 gears and the shifting seemed nice, but i have no clue what it's like on the highway. No matter what you do, second gear is just tall in these. Totally seems like they should have done the six speed a long time ago. lol
Whats crazy is with the current tire size with the 3.73 gear the truck is geared to top out at 170mph!! lol. It's nuts I really dont need to be able to reach that. Even though I would need a lot more power too haha. I think with the edge programmer and some 4.56's the truck will move quite nicely. It'll replace the mustang for strait line speed lol. Surprisingly now that it's lowered it handles really well. Feels more like a sporty fullsize car.
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Old 02-05-2011
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Any chance you could take a bunch of pictures doing the gear change and do a write up on it? That will then get moved in to the techinfo area when it's all set up. Put any information you can in the write up, like RPM changes, etc. That way the next person will have all those questions answered.
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Old 02-05-2011
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Originally Posted by danthurs View Post
Any chance you could take a bunch of pictures doing the gear change and do a write up on it? That will then get moved in to the techinfo area when it's all set up. Put any information you can in the write up, like RPM changes, etc. That way the next person will have all those questions answered.
I'll do what I can, but I wont be doing the swap lol not that mechanically inclined. Either a buddy of mine will which I will get all the info I can or i'll pay a shop to do it.
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Old 02-05-2011
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Well, do what you can. Thanks.
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