I'm looking for a XLT SuperCrew and I'm finding quite a few of these with this gear ratio.

I do tow a pull a boat/trailer combo that weighs in around 4,000 lbs.

I want the 3.73 ratio, but I'm hoping a few guys have pulled with the 3.55 ratio and can tell me their thoughts and whether they would hold off for a 3.73.

Thanks

 

I have a 04 SCAB with the 3.55 rear end and have no problem pulling a stock trailer with 3 horses in it. I origianlly wanted the 3.73 ratio but I fell in love with this truck and the axle was not a deciding factor for me. So I am completely happy with the 3.55.

 

a secondary issue is your engine.

if you have the 5.4, there will be so much low end torque you probably wont notice too much of a difference between the axle ratios.

 

Yes, I would definitely go with the 5.4.

Now I'm trying to figure out if limited slip is that important, I haven't seen to many 3.55's that have this.

Thanks for the feedback.

 

My XLT Screw with 5.4L and 3.55 is adequate. The 5% difference in ratio amounts to a difference of only 100 rpm @ 2000 and 150 rpm @ 3000, the rpm range where most of your driving will occur.

 

3.55 can handle that no problem. I have the limited slip with my 3.55s, but the only towing I do is dry (no boat-launching or anything).

If you get to towing 4k+, you may want to leaveoff OD on the highway to get some better RPM's, otherwise, no problems at all (I would leave OD off with the 3.73 also though).

 

If you plan to tow or simply want to get the most durabilty from you truck in terms of cooling and electrical system output you need the 3.73 axle. what has been nelected in these threads is that the 3.73 axle ratio is actually part of the towing package ( on my truck it is anyway) this package includes a larger radiator, a large addtional transmission cooler, a greater rated amp battery.
you will also recieve the factory hitch (which is a work of art in terms of its mounting) and wiring preinstalled as well as the relays and hookups for electric brakes. as far towing capacity goes ford rates the Screw 4x4, what i've got, at 8200 lbs
with the 3.55 and 9200 lbs. with the 3.73. btw subtract 500 lbs. if you have the 18 inch wheels.

 

Mine has the 3.55 with the trailer towing package... I don't tow anything but I've got it incase I do need it later. But the fx4's might come with all the towing package stuff I dunno...

 

I've seen quite a few with the 3.55 gear ratio and the tow package, so I don't think the 3.73 has anything to do with the tow package.

 

my payload package came with a 4.10 limited slip. kills the gas mileage but pulls like a son-bitch

 

The tow package's main parts are the hitch, wiring harness, and coolers for engine and transmission oils. The axle ratio is a seperate item. I also order the tow package to keep the warranty in effect if the tranny burns out; I know a few guys who ran into the service guys who knew the manual said the tow ratings were only if "properly equiped."

I've got a 5.4 with a 3.55LS and pull a 3000 lb bass boat. I can tell in the hilly areas that the top gear is too low, and must come out of overdrive. I'll go back to the 3.73 next time. My previous truck had a 3.73 and it would not come out of overdrive as much. It would also hold speed on the freeways better, with less shifting, and got better gas mileage.

So, if you only pull the trailer occassionally, the 3.55 will be OK; if you pull often, and deal with hills or high altitudes, get the 3.73.

 

Or you could realize that the difference between 3.55's and 3.73's with stock tires and the 5.4 isn't a big difference at all. If you're towing in hilly terrain, you really shouldn't be using overdrive anyways, but that's a whole 'nother understanding of transmissions and torque converters....

I may also add that I have the same exact tow package as mentioned above, yet with 3.55 gears... so ptooey on whoever says gears are in that package.

 

Yea, Deeno's correct. Honestly, there really isn't very much difference between the gear ratio's at all and the engine's got enough power to compensate if you're geared a little high. Even with the 3:73's It'll kick out of OD pretty easily when pulling hills with a trailer. I think it's the way they have the Transmission programmed. Plus you're below 2000rpm's heading down the road in OD anyway, with either set of gears.. (as long as you're below 75 or so)