Alright guys newbie question time. I have an 05 screw 5.4L w/ 3.55 rear end. I currently have the 275/65/18 oem tires, but I plan on changing them out for a set of either the 305/65/18 BFG AT or 33x12.5x18 Toyo MT.

I'm considering changing the rear end from 3.55. I did a search and the general trend appears to be 33=4.10 or 35=4.56/4.88. The tires I'm considering are between 33 and 34 inches. I think I want the 4.10's because gas mileage is important to me. I'm currently seeing around 15 mpg.

My question is what all is involved in changing out the gears? How difficult, how much does it normally cost, etc. I found a 4.10 ring and pinion set from Ford Racing. Would they be a good set or should I look elsewhere?

Thanks and sorry for being long winded!

 

Sorry guys, I have a few more ??

1. If I change the rear gears, do I have to change the gearing in the front diff. I have a 4x4.

2. If I change the gears, would that be the best time to add a locker in the diff.?

Once again thanks.

 

Hey man I'm in the same as you on this one.
I know a few of these answers:
1. Yes, with a 4x4 the same gears have to be the differentials. you will cause massive damage with wheels spinning at different speeds. There is a light at the end of the tunnel though. You can do the rear and front at different times, just don't use the 4x4 and make sure you tape the **** or something like that.

2. If you want a locker, install it now while the techs (or you) have the axles apart. It will save time, money, and differential oil.

3. As for your tire choice, with a 5.4 and 3.55's to start with, I would agree 4.10. I would maybe look into a programmer as well for a little more juice. I have 35's on mine and I'm getting steered toward 4.88's (cause im lookin for 37's), and with a programmer I will have more than enough power.

4. As far as brand, I looked at Ford Racing and I have heard Yukons are good as well. I think you will be ok with the Fords. Maybe someone else will chime in?

Oh and installation, thats a discussion in itself. Ive gotten quotes from 650 to 1400 just for labor. The 1400 was at a dealer and I laughed at him. This is a tough job and its not for the faint of heart. This should be done by a professional. If you have a friend with the experience and tools then I would consider doing it yourself. I can tell you I looked into pursuing this myself and the tools alone for the job cost at least 600 bucks, and i only planned to use them once for each axle.

 

1. Yes, if you ever want to use 4WD.
2. Yes, but do some homework, do you really need or want a true locker?

I would not advise you change gears yourself unless you have the required experience and tools. Leave this job to the specialists unless you have an experienced friend or something.

 

Thanks guys, I think you answered most of my questions. So I need to get a set of 4.10 gears for the front and rear differentials and I'm looking at $650+ for installation ( is that for both or just one?).

glc, I've done a little research, but not in depth. I'm not looking for a full time locker, such as the Detroit. I'm more interested in an electronic part time such as the Eaton E-Locker. It's the same system used on the Nissan Titan oem. I had an automatic locker in my last truck (G80) and I was not a fan. You could never be sure if it was going to lock up or if it would stay locked. I looked at the ARB air locker, but do not want to install an air compresor.

 

yea installation costs vary from place to place. Go with the place that offers you a good price and you feel will do a good job (Go where you get the good vibes man).
As far as parts, you will need two ring and pinion sets (both 4.10), master/minor install kits depending on how many miles you have on your truck (If its brand new go with a minor. I've got 50,000+ on mine and I have been steered towards a master), the locker diff(s), and gear oil/ friction modifier. That should round out the list.

(I'm assuming since you have the 5.4L that you have a 8.8 front and 9.75 rear diff.)
Also most importantly, make sure the 8.8 ring/pinion set is reverse cut!!!
(The forward differential is mounted backwards compared to the rear, so the gears have to move in reverse direction to propel your truck forward.)

Hope that helps! let me know how it goes. I'm working on some 4.88's in mine.

 

You might want to look at a geared LSD.

They can provide good performance without the some of the drawbacks of a locker...they're always in action, even on the street, and can transmit more torque than a conventional clutch-style LSD.

 

thanks for your replies. You have helped me alot. Thanks for the parts list. i started looking for all the parts, but it looks like I'm going to be limited on the diff locker. I haven't found one like I want for the 9.75 and I don't need one for the front.

tnsilverfx4, i will let you know how it goes, but it might be a while. still saving up. I just got the truck in april with 33k on it. So far I've installed a set a Bilstein adjustable shocks, Silverstar bulbs, Undercover Tonneau, 18" chrome edition lariat wheels, and upgraded the audio system.

 

Stay Away From 4wheel Parts Economy Gear, Sure They Are Life Time Guarenty But When I Took My Broken Ones Back They Were Out Of Them And On Back Order. I Ended Up Going With Motive Gear And They Were Much Heavier Duty.

 

CH2500
Please let me know who you have do your gears and how much Labor they charge I am also going to need gears and it is not worth buying the tools plus i have never done gears b4 and don't wanna F it up!!
Thanks!!!!

 

CH, I just put my lift and stuff on August. I know the pain of saving........ I'm still trying to pay that off.