I have a 2000 XLT 4x4 with a 5.4 motor and 3.55 rear. Is it possible to have the 3.55 replaced with 3.73's? The reason I'd like to do this is for towing. We are looking at a new boat which will be about 1000lbs under the current 7300 pound towing capacity. According the charts I've seen, my year with a 3.73 is rated for around 9000lbs.

 

You would have to change the ring and pinion sets for both front and rear axles. Big money for a 5% change in overall gear ratio...

 

Just make sure you get somebody that does gear swaps on a regular basis. I've heard quite a few horror stories of gear whine when some John Denver thinks you just drop them in.

 

Kick 'er up to 4.10s if you are forking out the dough for gears. Gear swaps are not that bad provided that you have the tools and patience.

 

I'd be paying somebody else to do as I don't have the tools or the know how. Are there changes that need to me made to the on board computer and transmission as well? 4.10's may be the way to go I guess I've just never seen them offered for the Expedition. I guess fuel economy is a wash either way

 

You might find that you get a little better mileage around town with the steeper gears. I know that I picked up 2-3mpg when I went from 2.73s to 3.73s in my Mustang. It will be even more noticable in a big truck like an Expedition since you have the mechanical advantage of the gearing to move all that weight. Depending on how much towing you plan on doing you could even go with 4.30s. I know that a lot of the V10 guys love 'em.

I would pick up a Diablosport Predator or SCT XCal2 for your truck. You can change gear ratios as well as tire sizes, shift points, rev limiters, etc with them. VERY handy tool to have.

 

I'd suggest getting the boat first to see how your "stock" Expy pulls it. Also ask, will the Expy tow said boat long distances, up hills, etc. where lower gears would be noticeable?

Several years ago I looked into swapping gears in my '00 4x4. I found the cost to be around $1200-1400 for front and rear axles including parts and labor at a couple different gear shops. If I were to do a swap, I'd opt for 4.10's minimum (but then again, I have 33" tires).

 

When I was towing the 25' enclosed trailer moving our stuff as well as a second trip with my Explorer in it there were times I wish I would have had at least 4.10s. The truck has the 5.4 with 3.73s and the towing package.

 

Thanks for all the input guys. To answer a few questions, the boat won't get towed all that often, longest trip is about 2 1/2 hours away which we may make a half a dozen times a year. Other then that it will stay at the local marina. The trip to the lake has some moderately long hills although the grade is not that bad. I do have a Hypertech Power Programmer II which is several years old but I did use it to adjust for the larger tires when Ford had the recall. 12-1400 bucks is actually better then what I was expecting to have the gears done, my issue there is finding a reputable shop to do it. My mechanic of some 17 years retired recently so I'm starting from sqare one. You may be right in trying it out prior to the gear swap. Now that I know it's a viable option and affordable I'm not worried as much about haveing to replace my tow vehicle which would delay the boat purchase. If I do replace the gears does anything need to happen with the transmission or does the computer adjust it accordingly?

 

Nope, nothing else needs to be done as far as transmission goes. You will have to use the hypertech programmer to adjust the gear ratio in the computer though.

 

Thanks again for all the input, the picture of your car makes me miss my 88GT which I sold this past fall still running like a champ. A few years back I had replaced the stock front clip and hood with a Cervini Ram Air hood and Stalker nose. After 19 years of never letting me down it was touch to her drive away, to many hobbies and to little money

 

Are you sure you will have to swap gears? I pulled a 8K boat with my 98 Explorer 5.0 AWD (3.73 gear 4 spd trans) and its replacement a 06 Explorer Ltd 4.6 (stock 3.55 6 spd trans rated for 7100 trailer) across state lines, up and down boat ramps no problem. I even pulled my buddies heavier boat but it wasn't weighed like mine. I don't use OD but have pulled it in 100F weather with 5 occupants (1 baby) and the a/c on. After 20K miles on the 2nd truck no problems so far.

 

Given my truk is rated for 7300 pounds and the boat with trailer empty is about 6200 pounds, till you factor in passengers and gear I'll be pretty close if not over what I'm rated for. I think by changing gears my tow rating will increase. In your case you are already exceeding what your vehicle is rated for and while you may be able to pull the boat down the keep in mind road tow ratings are related to safety as well as pulling ability. You may find that out in a situation where you have to make an abrupt stop only to find out that your boat wants to keep going. The other thing that is a big factor is where you are towing. If there are no mountains involved it's a lot easier to haul a heavier load

 

I understand that you are rated at 7300. But I stand by my original post. If you want to go by just the rating of your truck or your conscience then that is fine. I was stating that I have towed not occassionally but fairly frequently more with the same gear in a lesser truck (more hp though). Maybe my years of driving commercial straight trucks (no accidents) taught me how to accelerate slowly and anticipate stops and I am used to feeling (loaded) when pulling. Many want there vehicle to pull like "there is nothing behind it". I have driven mostly in Chicago streets/highways and have encountered many panic stops and the combo has not failed me yet. I have driven it to WI, MI and even a heavier boat to (w/3 passengers) IN through hills but both I also had to maneuver through the small tight city streets here. The old truck didn't have LO and the newer one I don't have to use LO to pull up the steep ramps (unless they are slippery). My vehicle has more than enough pulling power and for stopping power I check the trailer brakes (surge) and wheel bearings condition and the vehicle brakes. Now if you feel more comfortable with the steeper gears my all means I was just stating I think you have an adequate platform.

 

I wasn't trying to question your towing abilities obviously its working fine for you. The issue I have isn't whether it's feasable with my current vehicle but more along the line is it safe. All the articles I've read in Trailer Boat magazine about towing constantly harp on not exceeding your tow rating and not to forget to factor in all your gear when it comes to weight. Maybe they are just trying to sell more vehicles