Im looking to buy a 08 150 with 5.4L. It has 3.55 gears in it. The question is do the 3.55 gears give you much more mpg than the other? I know you dont buy a truck for the mpgs. Is it that the 3.73s give you a whole lot more towing power and make a big difference? And what would a 4x4 with extended cab and 3.55s have for a tow rating? Right now im not towing much, but may be in the future.

 

Get the VIN and look up at:

http://services.forddirect.fordvehicles.com/inventory/WindowSticker.pdf?vin="YOUR VIN HERE WITHOUT THE QUOTATION MARKS"

There isn't a lot of difference in MPG or towing capacity between the 3.55 and 3.73, but the owner's manual and door sticker will list the capacities. You can get a manual at https://www.fleet.ford.com/maintenan...ls/default.asp (along with a towing guide).

 

Thank you very much. That site was very helpful!

 

IF YOU ARE TOWING 3.73. THE OTHER THING TO THINK ABOUT IS THAT MOST PEOPLE END UP PUTTING ON LARGER TIRES AND THAT WILL LOWER YOU GEARING.

 

I would prefer 3.73 gears. I have an 06 with 3.55's and it tows ok, but i'm sure it would do better with 3.73's. I tow a 20' enclosed car hauler with a Mustang in it. They probably weigh in at 6700-6800 lbs. It'll run the speed limit and get 9-10 mpg towing.

 

I got an '04 XL, with 4.6 and 3.73. I can still get just over 20 mpg without trailer. Pulls a camping trailer all day at just over 18 MPG. Never drops out of high gear on hills.

 

my truck has the 3.55 as well and would prefer that it had the 3.73 instead. would it be a viable option to see about switching out for the 3.73? or would this be a costly enough operation that I'd be better off just trading this truck in for one that has the 3.73 gearing?

 

Bob,

What size trailer do you pull? I pull a 30 ft toy hauler with mine.. 373's 5.4.. And i get avg about 10 mpg's.. That was on a trip to FL and last summer to waktins glenn NY.. Let me say i know it's back there.
Mark

 

Muddedprairie, just a camping trailer pop up in the summer. No big deal, but after the first pull up north, I filled up, and showed just over 18 MPG. Speed, 65.

 

Is your truck 2 or 4 Wheel drive. If 4 you need to replace both sets in front and rear axles. The gear sets aren't super expensive, but by the time you buy them and have them installed properly it can cost a fair amount of money. Installing and setting up gears is not something I would recommend for the novice mechanic. If set up wrong you can have a boat load of problems. If you really like your truck and plan on keeping it for a long time then switch the gears. It's cheaper to switch gears than to buy a new truck. If you do switch gears make sure to get a programmer that will allow you to change the settings in the computer so that your speedometer is correct.

 

bob,

I here ya.... Wish i got 18 mpg .. good for you..

Mark

 

my truck's a 4x4 and I do really like it (and definitely planning on keeping it for a loooong time). so would my best bet be to go through the dealership to change out the gears or can I get this done right (and cheaper) by an independent mechanic? roughly what would this sort of upgrade cost? (ie: a few hundred bucks? a few thousand? more/less?)

 

if you are just changing from 3.55 to 3.73 it is not worth it. i had my dad's truck changed from a 3.55 to a 4.10. it cost me $800 total and that was a mechanic at work (dealership) doing it on the side. as far as dealership of independent it doesn't matter as long as it is done correctly. you need to know what you are doing when it comes to setting up rear end.

 

I probably would keep the 3.55's unless I'm maxing out the truck's towing capacity. The biggest thing to be concerned with when towing with 3.55's instead of 3.73's is tranny temp. As long as you keep it under 200 degrees F you shouldn't have any problems. It's not that important whether the dealer does a gear swap or an independent shop as long as they are competent. You may have to take it to the dealer for a reflash to account for the gear change. Most dealers charge .7 of an hour labor to do this.