4.56 Gears in... Backyard DIY style. Why didn't I do this sooner? install tips:
 

So to answer my own question "why didn't I do this sooner?" To put it simply.. I was stupid and being cheap!

This should of been what I did as soon as I lifted the truck and put larger than stock tires on! Holy hell, the drive ability of this truck is completely different. No more down-shifting up long gradual inclines, I can actually maintain a speed of 35mph going up those long gradual inclines without down-shifting out of overdrive.. SOOOO Worth it!

And the guys at diffsonly.com, made it even BETTER! The service their was fantastic, not to mention the partial refunds given after ordering and mentioning everyone here recommended them (overall, about $70 off each gear set)

So here are some install tips, as when I searched endlessly for 2 week about the 8.8" IFS stuff, i found nothing and i feared the worst, but it was actually very easy!

2002 F-150

9.75" rear end:

1. One of my rear rotors was frozen to the axle, go ahead and knock that thing loose, it will save you some headache's later on!
2. Get your bearings from the Ford dealership. They are Timken bearings and were $15 cheaper for the rear pinion bearing and $10 cheaper for the front pinion bearing than the same Timken bearing from any of the other auto parts places.
3. My front pinion bearing was about 3/32"-1/8" thicker than the Ford pinion bearing.. If this happens with your install, use the one that came out (only if the bearing rollers are clean (no scratch's, discoloration, flat spots, etc).
4. I was able to reuse the pinion shim and the carrier shims. The carrier shims needed swapped (passenger to driver, vice versa). This gave me a perfect backlash setting and drive pattern on the ring gear.
5. just over 3 Quarts of gear lube and 1 bottle of friction modifier filled up the pumpkin.


8.8" IFS axle:

1. Order an extra crush sleeve! The one I received was so hard, my 1/2" impact gun never even made it budge (same impact did the rear axle crush sleeve no problem).
2. Have a pair of snap ring pliers with a 90* tip handy. You will need these to remove the driver side stub axle.
3. Remove the passenger side axle extension tube from the center pumpkin. When you remove this, you may or may not get the axle extension that goes to the differential with it (most likely not). When you remove the extension tube, the axle extension and a bunch of other stuff will come with it. In the center pumpkin section, you will have the shift fork, locker collar and the axle extension. Between the axle extension and the axle (in the extension tube, yea i know, its complicated hearing but easier when you see it) there is a round spacer. Don't lose it, or forget to put it back. With the short axle extension (it has a gear looking section that goes into the lock collar, and the other goes into the diff end) removed and the stub axle removed, you can remove the center diff.
4. Again, i reused the factory spacers for the pinion and diff. The Diff spacers were also swapped from side to side. Backlash is just a bit tight (4 thousands), and the drive pattern looked good. Since i use my 4 wheel drive about 1 mile a week, I wasn't to concerned with the slightly tight backlash.

Oh yea... Have a friend to help out with getting the front axle in and out of the truck!


And the best tip of all..

QUIT SLACKING AND GET YOUR TRUCK RE-GEARED!!!! :banana:

Send me some money and I would definitely re-gear. Would love to at some point. Enjoy!

haha.. trust me man, it took me awhile to finally just say screw it and spend the money... even though with X-mas coming I shouldn't have. It has been well worth the expense though, so far i've gotten 20-30 miles more at 1/2 a tank than before the gears (150ish miles per 1/2 tank before, now sitting at 175-180)!

I am planning on doing my gears in my Exp but still working on figuring out what ratio to use. I have 3.31 gears now with 37"s. So I am looking at going to 4.11 gears. I am just not sure I can do the work myself.

For your tire size, id suggest 4.56's

At 75mph on 33's im turning 2500-2600rpms. With 37's you would probably be in the low 2000's

Thanks Thomas W
I would love to get back around 1800 at that speed but I dont know when I start to lose power plus I want to regain my fuel economy also all the while not losing torque.

When it comes to gears I am at a lose, so I am looking for all the help I can get. before I put on the bigger tires I was getting 16mpg on avg and now with 37"s I am getting around 12mpg. So more miles I would love to get back. Also How do I fix my speedometer and get it back to being more accurate.

I'd LOVE to get 16mpg! I get 11.5-12.5 with the 33's and 4.56's. I got the same thing when i was running 3.55's and 33's, the gas mileage didn't budge

You'll need a programmer to calibrate your speedometer after the gears and with the larger tires.

the only way you will see that mileage again is if you take off the 37's and go back to 31's.

you have over 400 pounds of extra rolling resistance in those tires.

i would suggest 4.88's to get the power back.

Thanks Str8t six
And this is why I am here to find out the best gears. I have gone to local shops and they suggest 4.11 or lower like in the 3s' but everyone on here is saying go with a higher number.

I want my power back plus fuel economy, but I understand with the tires there's a lot more weight than OEM. I am also planning on doing a V10 swap for my tired 5.4L, and then I will get even more power plus I should get fuel economy also. If I run 4.88 gears will I have any torque or will it be like a sprint car and have all speed and no torque.

I think your a bit confused.

A "low" gear is a numerically Higher number. A high gear is a numerically low number.

IE. A 4.88 gear is a lower gear ratio than a 4.11 and a 3.55 is a higher gear ratio than a 4.11

With a 3.55 gear ratio, the driveshaft has to turn 3.55 times for 1 rotation of the rear tire. With a 4.88 gear ratio, the driveshaft turns 4.88 times for 1 rotation of the rear tire. A 3.55 gear ratio will give you lower Rpm's during cruise since the driveshaft is spinning slower when compared to a 4.88 gear ratio.

So, A 4.88 gear will make you feel like you have more pulling power but lower your top speed. A 3.55 gear ratio will make you feel like you have less pulling power (the power and torque from the engine is same, but the higher/lower gear ratio makes the engine have to work easier/harder to pull) and a higher top speed

^ yup, exactly what thomas said.

JPORTER, what kind of driving do you do? is it more city or highway driving.

i turn 2K rpms at 60 with 35's and 4.88 gears. so you with 37's would be a little lower, probably around 1800 rpms at 60.

I split my time about even between highway and city, but when I am out chasing storms its all back roads when I get off the major highways.

Trust me as you can see already I know nothing about gears but I do know that everyone is telling me I need to change them, but the gear ratio is what I cant figure out to choose. Plus while looking at gear manufactures I have noticed some of them dont even make reverse gears for my front end in the gear ratios I have been looking at.

I know getting another 100 or 150 miles out of a tank is far out of left field but if I can get 60 I will be happy

Again thanks to both of you Str8t six and Thomas for helping.

I have a programmer but it hasn't done anything for my speedometer. So i dont know if I need to change the gear in the transmission for the speedo like in older transmissions. I have a analog speedo and not digital.

ok, if you drive over 70mph often then i would go with 4.56. otherwise i would chose 4.88's for more low end torque and less strain on the transmission and engine.

yeah a programmer wont help you correct your speedo, there is a VSS gear in your trans that you have to change out.