way2evil

What rear end ratio do I want? I am doing mostly street driving with an occasional load or trailer. The trailer will probably be once or twice a year, could be from 4k lbs to 8k lbs. I want a limited slip diff, that much I know. Looking at a Platinum w/ the 5.4l. Thanks in advance.

camstng66

3.73 lsd

ksks

I got some extra you can have!

JOHNWSC

I ended up going with 373 gears but I have the max tow package.I don't know if you need that to get those gears.I drove one with 331's and the 373's made a hugh diff.Keep in mind you'll have a 6 speed,and incase you want to go up a tire size or two they help the truck get along better.

pozi240

You don't NEED the max tow package to get the 3.73LS, but it comes with the package. (at least here in Canada), A very good option (and compromise if you will, lol), is the 3.55LS, which is what we chose for our truck (3.31 is not an option up here in the 4X4's)

Dirty Harry

I have the standard duty F150 with 355 gears. I have increased the tire size to 33.5".

I haul a slide in camper while towing enclosed snowmobile trailer or tow a 6000# travel trailer. It still has plenty of power!!

These new 6 speeds are geared pretty low. And if you'll notice the 373 is the lowest rear gear you can get. No need to get down into the 400's with this tranny!!

jhelrey

I personally like this rear-end...



....never mind, pic deleted....

Aggie*86

Personally, for onnly ocasional towing of relatively light weights I'd go with the 3.55 limited slip. Plenty of grunt. It always kills me when I see dually diesels pulling around a lawn tractor on a light duty trailer. People always buy way more than they need IMO. Its a manhood thing.

wesledip

I had just return from a snowmobiling trip and thought I would report in on how the F-150 did. My trailer weighed in at 6740#loaded and I cover 4 mountian states and 1800 miles with my familyin the FX4. I crossed at least 7 mountain passes with grades between 7 and 11 percent and all were above 4000 feet. The 5.4 with the 3.73 full dogged locker performed exceptionally well on the interstate and in the snow. I found myself only needing a little more power on Raynolds pass MT (6700 ft) 11% grade with a 40 mph head wind. Not too shabby but I still maintained about 67 mph.

If anyone is in the mountains the 3.73 is the sure way to go.

Oh, towing MPG about 8.75 +/- .5 @ 70 mph as opposed to 15.75 empty typical mixed driving. (calculated)
FYI

Ford - great job on the truck! luxury and power. I am glad I purchased your stock one year ago. Keep up the good work.

2009 Crew FX4 long bed
all black with HBS 2.5 leveler and Air Lift air bags on the rear
LT275/70x18 BFG A/T KOs

ak_cowboy

Get 3.73 and *search*
https://www.f150forum.com/f38/gear-ratio-45724/