Concensus on Tow Package Rear Ends

[Tom Nugler]

Greetings. While new to Expeditions I am not new to Ford trucks. This will be my 7th.
I am currently looking at a ’00 5.4L Expedition for towing my vintage Airstream camper trailer. This truck appears to have the tow package, two aux coolers by radiator, good sized hitch (labels painted over) and the 7 pin plug with metal cover. Rear axle code indicates it’s a 3.55 limited slip.
After lurking around this Forum for a couple of weeks and absorbing the nuances of the vehicle, one piece of information escapes me. Is there a general consensus of which rear end gear ratio is the most common on Expedition’s with the tow package?
While 3.73s were typical on 2WD trucks for towing, do the transfer case ratios allow 3.55s? The tow rating guides would lead you to believe so. For example, Trailer Life magazine’s tow rating guide for 2000 gives this vehicle a rating of 6900#, 7400# with 16” wheels. My trailer weights are not expected to be over 6000#.
Any enlightenment one of you Expedition Gurus could deliver would be most appreciated.

Thanks in advance,
Tom.

 

[pronstar]

I ran 4.10s on street rires (285/60R18) and loved them.

Locking out OD, and towing in third, I'd run about 2800 rpm or so at 60mph.

My truck came with 3.31s with the tow package which makes no sense. Even with the supercharger, it was a dog while towing heavy laods (6000 - 7000 lbs.) but when I swapped gears it was fantastic while towing and just driving.

IMHO a gear swap isn't worth it unless you make a two-step move.

Going from 3.55 to 3.73 isn't worth it. You're only talking about a couple percent difference.

 

[mustangswan]

I looked on the window sticker of my 2000 that came with the tow package and it said it came with 3.55 gears. I have a big boat (22ft cabin) that weighs alot and I could have used a bit more gear, but I did not tow that much. I found that peak milage was at 65 mph and got 18-18.5 mpg. If I went faster (70+), my milage dropped off. So a 3.25 or so would have been nice there. Conclusion the 3.55 were about right for my use.

 

[pronstar]

Originally posted by mustangswan
I looked on the window sticker of my 2000 that came with the tow package and it said it came with 3.55 gears. I have a big boat (22ft cabin) that weighs alot and I could have used a bit more gear, but I did not tow that much. I found that peak milage was at 65 mph and got 18-18.5 mpg. If I went faster (70+), my milage dropped off. So a 3.25 or so would have been nice there. Conclusion the 3.55 were about right for my use.

Keep in mind that your reduced MPG at higher speeds was the result of terrible aerodynamics, not the slightly higher RPM that the engine was turning.

Most folks report minimal to no mpg penalty running when swapping to 4.10s, or 4.56/4.88 (with larger tires)

 

[Tom Nugler]

Got It

Thanks for the input. Took delivery last night. Tan leather might not be the color for camping but the better half loves it, so it was a done deal.
Got them to knock off a grand from the price because the airbag light was flashing. Didn't tell them I am a tech, saw the loose plug under the seat and ran the codes on Alldata. Unplugged sensor.
Thanks again, post when I can,
Tom.