You really do need to keep an eye on the weight ratings. They are there for a reason.

Numerically higher gears will make it a lot easier on the truck when you are towing and you will probably get better mileage in town. Watch your ratings though.

 

I didn't take it as such I was just offering my experiences. I would not talk you out of swapping gears, as a matter of fact I would probably go a step higher to 4.10. I doubt the difference between 3.55 and 3.73 is that much seat of the pants acceleration/pulling power. When I used to race Mustangs way back it was hard to tell the difference between a 2.73 and 3.08 gear and so when I switched I went to 3.73 (pros suggested) and I felt that difference.

I have read Trailer Boat magazine for years (been boating/towing since 95) and I understand their position, how could they suggest a vehicle to tow something that it is not rated for liability wise. There seems to be 2 schools of thought at my ramps either the tow vehicle is grossly underpowered/rated or its overkill so not wanting to be unsafe my first tow vehicle was overkill. I had a 79 E250 ext with 460/C-6 trans for my 27' boat (Sea Ray 268) on triple axle trailer. It towed it fine except one day it was down and I needed a tow vehicle so I rented a Uhual (half ton) Silverado p/u with 4.8 engine to see if it could tow it and it did. By the charts the E250 was more suitable but by the maintenance costs I switched to renting the Uhauls (rated to approx 7K). My current boat I approximated the weight at 6500 with trailer so when I bought the 98 and 06 I thought I was within specs(98 at 6600#and 06 at 7100#). It wasn't until I weighed it I found out otherwise. Not many boaters actually weigh their boats loaded if they did I bet there would be more suprises.

I now also have a 00 Excursion with the V-10 and 4.30 gear and although they are proclaimed to be towing monsters (rated to 10K) the difference in towing my TT isn't as much as I expected. It does hold load in OD longer but the acceleration or braking with my TV is negiligble to me. I just came back from a 3400 mile trip through hills/mountains. Don't get me wrong it is better but the main difference I noticed is it can handle the tongue weight much better. That is why I have been lurking through the posts here I am doing some searching to see if it is feasible and I have found some who tow similar weights as my TT with the Expedition 5.4 and although it is close to or over the max depending on years I think it might be my next choice.

As far as unsafe if the factory rated your truck at 7.3K with the 3.55 and 9K with the 3.73 and the ONLY difference is the gears I think the worst case is it won't pull as hard, something that I don't think is normally considered unsafe. More variables such as wheel base, brake capacity, axle rating, hitch rating, suspension firmness affect safe towing more than .18 difference in rear axle ratio. For that difference you can put on smaller diameter tires to accomplish the same for less.

 

The Expeditions of that vintage were never rated over 8,000lbs.

 

With a boat that size, i would be looking at a large trans fluid cooler and ditching that lame excuse of a trans cooler inside the radiator instead of focusing on gears first. Like Buzzard said, get the boat on the truck first and see how it tows. Nobody can be sure that it will tow like a dog because of the gears, but you WILL have cooling problems going up hills with that boat and the gear and people in your truck. Start with the trans pampering first.

Oh, you might also wanna see if the hitch recall applies to your Expedition. You dont want that pretty boat to go flying off the back of your truck and killing like 20 people on the freeway and leaving you in debt.

https://www.ford-trucks.com/recalls/...y-2000/t-36280

YIKES!

You can go to the following site and type in your VIN number and the site will automatically give you recall status on your Expedition.

http://www.ford.com/owner-services/customer-support/recall-information

After thats all done, then ask about gears. Gears dont really make a noticeable difference unless you are changing the gearing by adding tires 33" and up...like me

 

Thanks for all the input. Seems the general train of thought is to bag the gear upgrade unless it gets real doggy on the hills. Given the advise on these threads if I do decide to go with a gear upgrade it would be 4.10's. I wasn't aware the factory tranny cooler was so mediocre any advise on an aftermarket kit? Thanks also for the link to the recall site

 

The hitch recall is a very real issue, as Fun_suv stated. Before the recall was anounced I pulled my 20 ft boat to Florida and when I returned I was shocked to see how lose the hitch was on the truck, some of the bolts had already fallen out. I atributed the strange feeling to the fact it was Dec. and I returned to Iowa in a snow storm. I took the truck to the dealer and made them put all new bolts in and then they replaced them again when the recall was issued.

 

I added a big ol' B&M trans cooler on my 4.6 Expy for towing. Cheap insurance compared to a trans rebuild. It routes in line of the exit side of your radiator cooler. The factory coolers work fine, til you start loading up your truck and towing heavy stuff. I had not heard of the hitch recall, but my Expy didnt come with a factory frame hitch, I added it on, because bumper hitch's are a joke. I did find it strange that my truck came with the factory trailer wiring, but not a frame hitch.

 

I understand your dilemma about towing. I currently have a 1998 Expy Eddie Bauer 4X4 with the 5.4 and have been towing a 23' travel trailer. It handles and brakes fine (added brake controller helped immensely), but towing up long or steep grades it does not have the power to maintain constant speed. I have 33" tires and have thought about upgrading to the 4.10 gears as well. The shop I spoke to about this claimed I would really loose gas mileage when not towing. I thought he was exaggerating, but would like to know if anyone out there has any input. I also thought about getting a supercharger to up the power, but I don't want to compromise the reliability since I have 165000 miles on the truck.

 

Like I've mentioned before, going with a numerically higher gear will usually get you better mileage when around town since the load on the motor won't be as high due to the mechanical advantage.

 

If you are running a higher gear numerically, won't the engine be spinning at a higher RPM, thus reducing fuel efficiency?

 

No. The stop and go strain will be less on the engine therefor requiring less fuel to move from a dead stop. Less load = less fuel.

 

Fuel efficiency is not all about engine RPM. If you are at 1500rpm and lugging the engine you will get worst mileage than at 2200rpm at 1/4 throttle. The numerically higher gears give you more of a mechanical advantage when accelerating and hauling heavier loads so that the engine does not need work as hard and use as much fuel. I get between 3 and 5 MPG better around town in my car after going from 2.73 to 3.73 and sacrificed 3mpg on the interstate depending on conditions.

 

You said Explorer with 5.4, 3.73.

Do you mean Expedition?