Re-Gearing

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May 18, 2004 | 10:18 PM

karenj

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Re-Gearing

I am planning on re-gearing my 03' Supercrew w/ 5.4L, 9 3/4" rear end to 4.10s. Currently have 3.55s w/ 285/75/16 tires. According to calcs. i am running actual ratio 3.26 w/ my tires and with 4.10s actual ratio will be 3.76. I tow a 6200# TT loaded and with my current ratio it's a little dogish on the low end. My ? is would this be a wise move to save on wear and tear on tranny and engine, I think it is, but I want some feedback pros & cons and for those of you who have made this move, and are you happy with it???

Thanx Rich

May 18, 2004 | 10:56 PM

peteyg

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From: Temecula, CA

Re-gearing moves your torque curve lower. You will not regret it. Especially if you're towing and have larger than stock tires. It will also help you get your power back, and will for sure ease the strain on your transmission.

If you want to trade some of your top end speed for better low end torque, consider going to 4.56. You will lose a little gas milage, however, because it'll move your cruising rpm higher. You'll love the hot-rod feel, though. With the 285's that's a 32" diameter tire, so the 4.10's will feel good for you. If you have any plans of lifting it and putting bigger tires on, then 4.56 is a better bet.

May 19, 2004 | 05:58 PM

SoCalDesertRider

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I went through the same thing you're going through now. My F350 had 3.55 gears and a 351 engine with 33" tires and it was a real dog for power. I switched to 4.56 gears and what a difference! My gas mileage went up a little too, since I don't have to put my foot in it to get the truck moving like I used to. I don't have overdrive, so I lost my high speed cruising mileage, but that's fine with me, I keep the speed down to 60mph or less it gets good mileage. With your overdrive tranny you should be fine with 4.56's and your ratio would be about 4.30 effective, with your 285 tires. 4.10 would also work, but since you're towing a fair amount of weight there, I would say 4.56 would be better. With an effective ratio of ~4.30 and an overdrive ratio of ~0.70, your final ratio in overdrive would be ~3.00, which is high enough for cruising at freeway speeds and still get descent mileage.

May 19, 2004 | 09:35 PM

karenj

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Thanks socal and pete for the reasurment

, I have made my apt. for next week to re-gear, I am leaning towards 4.10s right now due to the fact I tow seasonally, I'm sure anything I do will help

I'll let ya know how it comes out. Rich

May 28, 2004 | 11:41 AM

karenj

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*UPDATE* Had the gear change done to 4.10s two days ago and what a difference it made. I am still in my break in period, but i am looking forward to trying it out towing. I'm getting my speedo,odometer and shift points corrected by my dealer next week so everything is correct. thanks for all the input Rich

May 28, 2004 | 05:26 PM

95f150

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From: Alberta

Hey can you fill me in on how long it took to get new gears installed, price for gears etc. I have 35" tires and stock 3.55s it sucks bad. i want 4.56 gears and i was quoted $2000 for everything in canada. parts were approx.$650 and rest was labour. is this hard to do yourself? i have a ford 8.8" and a d44 ifs.

thanks

May 28, 2004 | 09:28 PM

SoCalDesertRider

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From: USA

Rich,
Hooray! Glad you like the new gears! It's a great feeling to have POWER again isn't it? I know it's hard to avoid the urge to 'test them out'. Just wait for a while untill your break-in time is up...