I pull a 19 foot camp trailer with my 5.4 that weighs about 5000 lbs. I wouldnt want a smaller engine doing it. I'm in utah and we have some narly hills. I can only do 45 up I80 just outside of Salt Lake.

 

BTW, gas mileage is going to be negligible between the two, if that's one of the deciding factors for you...

 

If you do end up getting a 4.6 you should definently regear to 4:10's or 4:30 along with a custom towing tune from PHP

 

I have the 5.4, and my wife has the 4.6, and it will do the same job any day. The 4.6 has a little less power, but unless you like getting 14-15mpg without a trailer, don't get the 5.4.

If you pull stuff every day, then the 5.4 would probably be your best bet. If you only pull your boat once in a while, the 4.6 will be fine. And you'll appreciate the 18-19 mpg's.

 

crap! i finally found one i like. it's a 2009 5.4L but i noticed the axle ratio is 3.15

i was always told the lower the gear ratio, the poorer choice for towing. what do you guys think?

 

Wow that is a pretty low gear! Im guessing its not 4x4? If you were to buy it you would probably need bigger gears like previously mentioned. What makes you like that exact truck the color? If so see if there are any other dealers with that same color truck just with a different gear ratio

 

Not necessairly. If you don't pull everyday, it will be great, because it will get much better fuel mileage! If you want a lower gear ratio to help you with the hills just turn O/D off when towing! Pressing the button is much easier and cheaper than regearing, and you can turn it back on when on flats, or not towing.

Regearing is for people that need the lower gear ratio all the time.

 

Maybe a stupid question.. but what exactly does O/D do?

 

OD is basically a gear reduction. typically 3rd is a 1:1 ratio. that ratio is typically dropped to .75 area with OD for lower cruising rpm

 

Oh alright cool thanks for the info

 

Don't forget that the 09 3 valve 5.4's and 4.6's have the new 6-speed auto, so 3.15's might not be as bad as it sounds. 4.10's would still be awesome, but you can do that on your own for a lot cheaper.

 

I can compare this to previous cars I have owned or still own.....



the IROC..... you wouldn't buy an IROC-Z with a 305 would, you?
No, you'd buy the 5.7 version...

GTP- You wouldnt buy a N/A 3.8 Grand Prix would you?
No- you would get the supercharged 3.8

the Expy- well, that doesnt matter much now, that junk 4.6 is sitting in the garage and truck has a new 5.4


come on... you ALWAYS get the bigger engine!!!

 

I wouldn't touch a 5.4 with the standard 3.15 axle and pull any kind of load. Your are approaching issues like they had with the far too common Titan axle failures. Far too much torque generated by the now 6 speed auto going into a far too high gear ratio and on larger tires. Heat is going to be an issue and failures will be common. You heard it first on roller derby.....er, F150online.

 

yea i'd have to agree with ctc. if your gonna buy something new you might as well do it right. and 3.15 gears will kill towing mpg. yea the new f150's have a 6 speed auto but dont forget it still has a 1:1 gear and o/d which is where you'll really notice the power loss and it'll be shifting in and out of o/d alot more compared to a 04-08 truck with 3.55 or 3.73 gears. 3.15's are strictly a fuel economy gear ratio. does anyone know what the ratios are in those new 6 speed trannies? i wouldnt settle for anything under 3.55:1 axle gear ratio for towing, thats just me though.

 

Goes to show ya what happens when several folks are trying to get info from you when you are reading a post. The standard axle ratio is 3.31, not the 3.15. The 3.15 is part of the SFE package for "superior fuel economy". It is not intended nor should be used as a towing axle ratio. The 6 speed auto gear ratios look like this:
1st- 4.17
2nd- 2.34
3rd- 1.52
4th- 1.14
5th- 0.87
6th- 0.69

At least that's what we got from Ford. There is the optional 3.73 gear set that would be much better for towing.