I currently have 3.73's with a 4.0L SOHC, but will re-gear when I put on the Superlift and 33's. So should I go with 4.10's or 4.56's? Most of my driving is in the city so I want to go with what will give me the most power to mileage ratio. I'm not concerned with re-gearing strictly for mileage. As far as future plans, 35's may be possible, although not likely. What say you?

 

4.56s

 

that wat i have 3.73 and i get 15 or 16 mpg in town reagearing is a **** load of money or if u do it a lot of work. ive found kits for 4.10 for 600$ plus labor if ur not doin it. as long as u dont drive it like a retard u should be good on mpg. if its power ur gears are fine to push those 33's around ive towed a full size up a hill in my rig no problem.

 

It is quite a bit of money, but I am doing all of the work myself so I want to get everything done at once. I don't want to have to pull everything back apart down the road. Not only that, but I don't want to lose anymore power. I noticed the loss of power with 32's so 33's have to be worse.

 

4.56s

 

i havent lost so much that i cant do things like pull my boat on the freeway idk up to u bro but if i had to pick 4.56's x 3

 

I'd do 4.56. 4.10 will be plenty adequite, but you mentioned the possibility of 35's down the road...that's what made my decision for me.


Here's what I'd do as I was in the same situation as you at one point... I'd get a front axle from a low mile truck from a junkyard or off a member or off craigslist. I used a 30,000mile Sport Trac axle purchased from a member here for less than $100. That way, you can just swap in an already geared axle when doing the Superlift install....no waiting for a shop to finish that axle so you can get back on the road. Then....later down the road a little bit, you can drop the truck off at the axle shop and have them do the rear for you. Then....you'll be all geared up. Just leave the front shaft off if you're stuck with two ratios at once.

Of course...I'm assuming the superlift install is being done at home or a friends garage, not at a shop. If installation is being done for you, nevermind on the above comment. lol.



RangerBoi.... you've got the OHV...those engines take way more kindly to tires compared to the SOHC. OHV's have torque down low...SOHC's have torque up high.

 

ok that makes sence. cuz im lookin into 4.10 when my BL gets here for those 35's

 

4.10 and 35...if ur gonna pay to regear y not go all the way....if u do 4.10 ur gonna hate urself.....if i was running 35 and was gonna pay to regear id do 4.88 or even 5.13...IMO

 

4.56, no question about it. My sport trac had 4.10's and with 33's it was a bit sluggish. Not bad mind you, but I would never throw a bunch of money at it to gear it that way intentionally. I re-geared to 4.88's with 33's because I found a front diff with 4.88s and an aussie already installed, and it worked well where I was living/driving. Ideally I would have gone with 4.56.
Take Shane's advice about the front, you can save a bit of money if you can find a front diff already re-geared. Usually anyway. Unfortunately the diff I got had a bad pinion seal and the seller didn't tell me. I ended up having to pull it all apart again.

 

mostly city, definitely. my truck had 3.73 and i lifted it 5 inches with 33's, added the 4.56's. awesome torque, and you will get better mileage than 4.10's in the city. the lower the gear the better in stop and go, but crappy highway. taller gears have the opposite effect.

 

4:56 and be done with it, dont waste your time with 4:10's

 

I added alot more of my thoughts in a PM reply...what it boiled down to was this:

If the truck has 3.73s and running 33's, regear it to 4.56 if budget allows or keeping the truck 'til it does'. If not, go junkyard 4.10 axles. Swapping in junkyard low mile axles would cost easily under $500. Under half the price of getting gears swapped in.

BUT...if the truck has 4.10s and running 33's, it's pretty darn drivable and it isn't that bad at all...... is the juice of just a small amount of added drivability really worth the squeeze of the $1200 or so for a full gear swap? Same theory applies to putting in 4.10s into the existing axles in the truck that are 3.73's.

The OP's situation to me is like this: 4.10 and 35's = 3.73 and 33's. About the same effective ratios of about 3.60:1. Bump up a gear size and effective ratio changes to about 3.73. Bump up again, and effective ratio is about 4.10. OP bumps to 4.56, truck will feel like it is on stock tires and 4.10s.


Again...this is coming from a gearhead who does is own work and installations(except for the gear install itsself). And again still....if you know people and who to go to, gear swaps can get pretty affordable. My 4.88 swap ran me $700 for parts and labor not including the new axles that I used. So if you've got a couple days downtime, pull the axles, drop 'em off at the gear shop, have 'em geared, and it'd likely be cheaper in the end too.

I feel like I'm talking too much...I'm gonna stop now. lol.

 

won't 4.56s run high in the rpms when your driving on the highway? I say go 4.10s cause you said you doubt you'll get 35s

 

33/30 = 1.1

1.1*3.73 = 4.10

add in the weight of the tire and id run 4.56s

if you were to do the math of a regular edge with 4.10s (many trucks came with 4.10s stock with 30" tires)

you would come out at 4.51 and the closest ideal gear is 4.56

 

^what I was trying to say with alot less words. lol.

I can't find my damn formulas!! lol.

 

4.56s for sure!

 

you always got this handy gear guide......

Gear Ratio Guide For Larger Tires

 

This calculator will tell you what you need to know. However I forget what the ratio of O/D is on the 5r55e. I used this before re-gearing my sport trac and it was pretty much dead on.
MOTOR - A Rear Axle Calculator

 

.75 is OD

actually there is an even better one. but i dont remember the site, its more geared to 4wd apps

 

I knew someone would know it off-hand.

4.10 - 32.5" tires, in O/D at 2225 RPM = 70 mph.
4.56 - 32.5" tires, in O/D at 2500 RPM = 70 mph.
4.88 - 32.5" tires, in O/D at 2650 RPM = 70 mph

And if the truck came stock with 3.73s and 30" tires, 4.10 gears would put it back to stock with 33s. But it doesn't account for the extra weight and drag.

 

Thanks for all the help! Based on all the input, I am definitely going with 4.56's. I estimate the total cost to be about $600, which is not bad for the power difference it will make. I have a family member who will do the actual install of the gears as they have all of the various indicators and depth tools so labor is not an issue.

 

Now you might be talking about a diffent truck, but my '03 turns over 2500 rpm with 33's at 70 mph.

 

sounds good. you will like the new setup!

 

is your speedometer calibrated to the tires? if not then if your speedo reads 70 your probably going close to 80