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What did I just buy?!?! Bronco ranger conversion

09fx4guy

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Vehicle Year
2009
Make / Model
Ford
Engine Type
4.0 V6
Engine Size
4.0
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
Pre Key w/ #1 Bars
Tire Size
265/70R16
Go with the 4.56, unless you plan on upgrading to larger tires at some point. That is a real nice find. I can't find anything around me for under 1000 that nice. Most people want 1000 for something rusted to hell that's missing and engine and trans, but "they know what they have".
 


franklin2

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Bronco II
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Let's do some figuring. I am assuming you have the M5OD tranny. This site lists the gear ratios for one mated to a 4.0 as

1st: 3.40

2nd: 2.05

3rd: 1.31

4th: 1.00

5th: 0.79

Reverse: 3.40

So with your 3.73 gear your final ratios are;

1st: 3.40x3.73=12.7

2nd: 2.05x3.73=7.7

3rd: 1.31x3.73=4.9

4th: 1.00x3.73=3.73

5th: 0.79x3.73=2.9

With a 4.88 gear your final ratios are

1st: 3.40x4.88=16.6

2nd: 2.05x4.88=10.0

3rd: 1.31x4.88=6.4

4th: 1.00x4.88=4.88

5th: 0.79x4.88=3.9

So right now you have 3.73, the tires will be the same. If you keep the tires the same, but go to 4.88 gears, your top ratio will be 3.9. That is just slightly higher but very close to the 4th gear ratio you have now with the 3.73. So you already know what it will be like driving in 5th gear with 4.88, it will be very much the same as driving in 4th with 3.73. Do you like driving the highway in 4th gear now? If it's too many rpms, you might need to think about 4.56 gears. If it is still lugging right now in 4th, you may need to go even higher. Do they make 5.13's for that rearend?
 

sgtsandman

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Location
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Vehicle Year
2011
Make / Model
Ford Ranger XLT
Engine Type
4.0 V6
Engine Size
4.0 SOHC
Transmission
Manual
2WD / 4WD
4WD
Total Lift
Pre-2008 lift
Tire Size
31X10.5R15
Hey everyone update on the issues I was having. Found corrosion in the ecm. Found a used ecm and made the truck driveable. Truck started throwing mass air codes. Tried cleaning and same issue. Found a used mass air flow sensor and installed and truck ran great for a few days then started having a miss and a gas smell found #1 injector leaking out of the electrical connector. Installed 6 injectors and new Orings. After all that truck is running great and very reliable so far.

On to the next project on the rig ...gears. Truck has 4.0,5speed, 8.8 rear, Dana 35 front, 33x12.5 tires. Currently has 3.73s that is to high of a gear. To much effort to take off and 5th gear is unusable.

Do I want to go with 4.56s or 4.88s? I will stay with the 33” tires. I do some highway driving but not much. I wasn’t sure if running a bit more rpm is worth the extra gear for 4.88?
I would go with 4.56. 4.88 will be too low.
 

gw33gp

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Ford
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4.0 V6
Engine Size
4.0 SOHC
Transmission
Manual
2WD / 4WD
4WD
Tire Size
33"
I run 4.56 gears with 33" tires and am very happy with that combination. It does very well on highways and Interstates at whatever speed I want to drive at. It is just a little lower gearing (higher rpm) than the factory 4.10 gears with 31" tires. With the slightly overall lower gearing, it improves the off-road performance.

I ran the 33" tires for a short time with the 4.10 gears and did not like that combination. I think that might work better with an automatic transmission but would still be somewhat sluggish in acceleration. I also run 31" street tires with the 4.56 gears when I am not going on an off-road trip. It is OK around town but I don't like the highway rpm at the speeds I like to run. Running 4.88 gears with 33" tires may not be as bad as 4.10 gear with 31" tires but, I think you would still be running higher rpm than you would like.

There are a couple advantages of running 4.56 gears with 31" tires. Acceleration is much better but sucks up more gas doing it. It also tows very nice and actually gets better gas mileage on long haul towing than it did with 4.10 gear and 31" tires. So, if you want great acceleration and don't care about the drop in gas mileage along with higher rpm, and/or you tow a lot, then go with the 4..88 gears with the 33" tires. If you do a lot of slow rock crawling, the 4.88 gears would be worth considering. Otherwise, go with the 4.56 gears.
 

sgtsandman

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Make / Model
Ford Ranger XLT
Engine Type
4.0 V6
Engine Size
4.0 SOHC
Transmission
Manual
2WD / 4WD
4WD
Total Lift
Pre-2008 lift
Tire Size
31X10.5R15
Take a look at this chart. It will give you a good idea what gear ratio is going to do what with a given tire size:

 

Mtcrss546

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Location
Springfield Missouri
Vehicle Year
1989
Make / Model
bronco/ranger
Engine Type
4.0 V6
Transmission
Manual
2WD / 4WD
4WD
Tire Size
33x12.5x15
4.88 seem to be a good fit for how I used the truck. So now I’m Looking for a set of used 4.88 gears if anyone has some for 8.8 and Dana 35. Posted in wanted section also.
 

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