I'm trying to sneak in on this year model clearance ford has going on right now. I'm looking at a supercrew lariat 4x4 w/ 6.5 ft bed. However, all I can find is 3.55 limited slip when I would rather have the 3.73 limited slip. I plan on putting on a 4" lift and 35's (and I wouldn't lift anymore b/c I plan on daily drving the truck in the future and don't want the truck to be impractically high when working with the truck) but that won't be for a year or so. I'll pull a 22' camper a handfull of times a year and maybe an occasional load of wood as well. Should I hold out for the 3.73 limited slip, to save $ on a regear when I get the lift and tires, or just get the 3.55 limited slip and upgrade to the 4.10s when i eventually get my lift and tires? Also, is a regear a big deal (should read more $$) when you have a limited slip axle? On a side note is it 4.10 or 4.11? Thanks in advance for any input and advice!

 

IMO if your gonna be pulling a camper look at 4.56 gears not 4.10's. I have a 4" lift and 35's with 3.55 gears and towing is a pain. The truck will still get up and go but with no authority like it did with stock tires. Im going to be upgrading to 4.56 or possibly 4.88's in the next couple months as i tow a boat and sled trailer.

 

If you're going to lift it, add bigger wheels and tires, and tow a trailer, you should shoot for 4.56's. 4.10's are good for 2WD's with stock/slightly bigger than stock wheels and tires.

 

As said id look 4.56's

It doesent matter different companys are gonna say 4.10's or 4.11's... when you look for gears if you go with 4.56's youl find em from 4.56-4.58 the rear may be 4.56 the front 4.57 that want matter aslong as its not like 4.56-4.30

 

I have 4.10 gears. They are sufficient. The rest of the year when you're not towing, you'll have decent mileage with the 4.10 gears. If you were towing every day, as if you were on a farm or in a commercial situation, then I would go with the 4.56. However, in your case, you simply don't need it.

 

With the 6 speed tranny, you may not even need to regear at all. However, I would get a programmer and a tune.

 

I would see how you like it with stock gears/oversize tires before spending money on a regear. Then if you tow stuff and 35's i'd say atleast 4.56. The oversize tires basically numerically lowers your gear ratio which is a higher gear. I think 4.56's with 35's would be like towing wtith stock tires and 3.73's round about. 4.88's would be about like stock tire size towing with 4.10's. Somewhere around there anyway.

 

thanks for the help guys!

 

The 4R70W, 4R75W, 4R70E, 4R75E, AODE all had a 2.84 first gear,
2.84 X 3.55 rear = 10.08 overall ratio
2.84 X 3.73 rear = 10.59 overall ratio
2.84 X 4.10 rear = 11.64 overall ratio
2.84 X 4.56 rear = 12.95 overall ratio

The 4R100 had a 2.71 first gear,
2.71 X 3.55 rear = 9.62 overall ratio
2.71 X 3.73 rear = 10.11 overall ratio
2.71 X 4.10 rear = 11.11 overall ratio
2.71 X 4.56 rear = 12.35 overall ratio

The new 6 speed 6R80E has a 4.17 first gear ... and a 2.34 second gear
4.17 X 3.55 rear = 14.80 overall ratio
4.17 X 3.73 rear = 15.55 overall ratio
4.17 X 4.10 rear = 17.10 overall ratio

2.34 X 3.55 rear = 8.30 overall ratio in second gear

The new 2010 Ford Truck 6R80E 6 speed transmission with it's low geared 4.17 first gear and a 3.55 geared axle is a lower overall ratio than either of the pre 2010 4 speed automatics in the F-150 even if you were to re-gear those pre 2010 trucks with a 4.56 rear axle (and front axle) gear.

Hell, second gear in this transmission is not all that far from first in the 4 speeds!

Another way to look at it is 6R80E's first gear 4.17 X 3.55 rear = 14.80 overall ratio devided by 2.84 first gear of the majority of the 4 speeds = a 5.21 rear gear that would be needed with a 4R70W, 4R75W, 4R70E, 4R75E, AODE ... to match the 6R80E in first gear pulling.

The 4R100 with it's 2.71 first gear needs a 5.46 rear gear to match it.

Numbers don't lie.

Feel free to check the math, sometimes a finger hits the wrong button.

 

Wow this is pretty interesting. Sounds like re gearing is pointless unless you are going REALLY big but that is less than 1% of truck owners. I think a better solution is increasing the rpm shift point if you installed bigger tires and that can be done with a tune. Last I checked, parts alone for re gearing are close to $1000 if you want to do it right on a 4x4.

 

You can use this site to determine what gears are needed to get back to OE ratio after changing tire size.
http://www.4lo.com/calc/geartire.php

The big problem with larger tires and either a 4 speed or 6 speed has exactly the same gear ratio in the final overdrive gear, which is about .71 to 1. When towing this becomes the problem. Unlike newer models where you can lock out higher gears, the 09 and 10 did not have the select shift transmission available. The only thing they had was the tow/haul mode which still went all the way to 6th gear. With too high a final gear ratio the transmission will be hunting for the right gear when hitting headwinds or hills. This could happen whether towing or not. Also the tires are heavier and cause similar problems to having a higher gear ratio.