Towing with 2010 Mountaineer 2WD 4.0L and 3:53, Mods Needed? | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Towing with 2010 Mountaineer 2WD 4.0L and 3:53, Mods Needed?

danpaw

New Member
Joined
January 30, 2014
Messages
2
Reaction score
0
City, State
Michigan
Year, Model & Trim Level
2010 Mountaineer
Hi all, Dan here from the west Michigan coast... Have recently bought a '10 Mountaineer and have lots of questions regarding towing.

My unit has a full-size AFTERMARKET class III/IV hitch installed (no controller or large trailer plug yet, that will be the first thing I do). 13k miles on the odo. Has a factory tranny cooler mounted in front of the radiator. Has the 4L V6, w/ 3.55 gears, O/D switch on PRNDL post, 4 conductor factory trailer wire. I hope to tow a smallish travel trailer with it within a year or two. (~3500 -4000 lb class, 20-22 ft). I have a strong background in electronics, electricals, and prototyping, so not afraid to get my wire strippers and soldering tools dirty.
My big questions: what do I need to do to make this little truck tow the 5305 lb capacity that it claims to have? 3.73 gear? Extra oil/ Larger trans cooler? Suspension upgrades?



The 2010 Ford Towing guide indicates that for the Explorer/Mountaineer, the class III/IV factory tow package was only available on the V6 with a 3:73 diff... So, is it a case of needing the 3:73 (and potentially a different Trans/Motor ECM with different software, and potentially a larger tranny cooler) or are they only indicating that you could only BUY the larger hitch along with the 3:73 diff in a factory package? Put another way, what do I need to add to the existing 4.0L / 3:55 setup to tow the full 5305 lb rating? I can't see the lower gears hurting me if I keep speeds reasonable..
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





The V6 wiht 3.55 gearing is limited to 3500 lbs MAX. And that's with nothing in the Mounty except the driver. Put 500 lbs of passengers in the truck, and you can only tow 3000 lbs of trailer.

Adding the extra hitch, wiring, and cooling capacity that would have come with the HD towing package is great. But it's worthless (IMO), since you don't have the right gearing. To get the 5000+ rating, you'd need to swap the gearing to the 3.73. The gearing changes are necessary to prevent overloading the drivetrain a low rpm situations (like starting from a dead stop). Numerically increasing the final drive ratio lets the engine rev quicker to get to the higher torque range, which is less stressful on the engine. Over time, this lengthens durability.
The V6-5speed drivetrain does this by changing the axle ratios, increasing max tow rating from 3500 to 5000+.
The V8-6-speed drivetrain does not need the axle ratio change, because 1st gear was made extra-low (numerially high). So the V8 retains the 3.55 gearing, but gets the full 7000+ rating.

If you are dead-set on using this truck, I would look into the gearing before you waste a lot of time on the other items. But I wonder why you bought this truck, knowing you were going to be towing a full-height 4000 lbs trailer. Just curious. Maybe this was a thought after you bought?

Some will soon reply that they have towed 5000 lbs with your drivetrain (w/o the HD tow package) "without any problems". It will be entirely up to you whether you want to risk your truck's drivetrain based on such comments. The problem is that you won't know you're doing damage for a few years.
 






Like the Brakeman said, gears are the first and probably the most cost effective way to increase the tow capacity. Since yours is just 2wd, you'll need just the rear pumpkin, and if you do not want to mess with gears, you can buy the whole unit and just swap it. There are used ones for few hundred bucks, or remanufactured ones for about 1000. But maybe you can find a shop that will do it for 500. You'll will have to adjust the speedometer, in my old TBird with the same rear end (IRS 8.8 in) all I had to do was change a little speedometer gear, not sure how it is on Explorer.
 






The V6 wiht 3.55 gearing is limited to 3500 lbs MAX. And that's with nothing in the Mounty except the driver. Put 500 lbs of passengers in the truck, and you can only tow 3000 lbs of trailer.

Adding the extra hitch, wiring, and cooling capacity that would have come with the HD towing package is great. But it's worthless (IMO), since you don't have the right gearing. To get the 5000+ rating, you'd need to swap the gearing to the 3.73. The gearing changes are necessary to prevent overloading the drivetrain a low rpm situations (like starting from a dead stop). Numerically increasing the final drive ratio lets the engine rev quicker to get to the higher torque range, which is less stressful on the engine. Over time, this lengthens durability.
The V6-5speed drivetrain does this by changing the axle ratios, increasing max tow rating from 3500 to 5000+.
The V8-6-speed drivetrain does not need the axle ratio change, because 1st gear was made extra-low (numerially high). So the V8 retains the 3.55 gearing, but gets the full 7000+ rating.

If you are dead-set on using this truck, I would look into the gearing before you waste a lot of time on the other items. But I wonder why you bought this truck, knowing you were going to be towing a full-height 4000 lbs trailer. Just curious. Maybe this was a thought after you bought?

Some will soon reply that they have towed 5000 lbs with your drivetrain (w/o the HD tow package) "without any problems". It will be entirely up to you whether you want to risk your truck's drivetrain based on such comments. The problem is that you won't know you're doing damage for a few years.


I first want to say that you are ABSOLUTELY correct in all that you have said. You should not technically tow more than 3500 with the 3.55's.

I just want to give him my opinion and experience and the results of my research.


Here it goes..
I thought very long and hard about this as I wanted to upgrade my towing capacity and do it safely for the truck and other drivers on the road but to also not go overboard on unnecessary cost.

What I first did was ask myself...how much am I going to tow?

I'd like to say first off that I used to own a 2002 ex with a tow package and 3.73's so I know what it feels like to have the tow package and I know what it feels like to not have it.

The answer for me was less than 1000 miles a year. So that is one factor that I considered. But that being said the greatest factor was this....


Using a gearing calculator that consisted of the transmission gearing, differential gearing, tire size, and transfer case gearing (its 1:1) I determined that:

In first gear at 6000rpm with stock tires (keep in mind your results may differ slightly as the Aviator tire height is probably a tad different than mine but the principle is the same)
with 3.55's you will be going 42mph
with 3.73's you will be going 40mph

In 4th gear at 6k rpms (redline)
3.55s you are going (theoretically of course) 145mph
3.73s you are going at 138mph

go online and search for one of these calculators and do it yourself if you want (actually I encourage it) but you will find that the difference is nominal. Even at totally unrealistic speeds the difference is only 7mph!

This correlates to about a 5% difference in gearing when you do the math.

Consider this, when a manufacturer makes tires they are required to be in a plus or minus 10% range in regards to the tire size. That means that a new tire (of the same size on the sidewall) could be up to 10% larger or smaller than the tire that you have on at the moment.

factoring this in the difference in 3.73's to 3.55's could grow to 8% or be reduced to 3% or so....



What I am saying is that 3.55's and 3.73's are a VERY similar gear ratio. If you but a 1.5 inch taller tire for your 3.73 geared explorer the axle gearing is theoretically brought down to 3.56...thats just how close they are!

Finally, I don't tell myself all this to help me sleep at night because I don't have 3.73's I say this because it is the truth. the ratios are very similar and unless you tow all the time you don't really need to make the switch in my opinion. And, if you did tow all the time you are much better off going with 4.10's anyway. 3.73's simply aren't worth the cost and hassle to install if you don't already have them for 95% of people's uses in my opinion.


Again, I'm not trying to say that there is no reason Ford would put 3.73's and 3.55's in a vehicle but I am saying that the reasons are very nominal and could partly be a marketing thing if nothing else as well.


When up to speed these differences are negated as well. The transmission can hold lower gears longer (albeit at the sacrifice of passenger comfort of having to listen to the engine) to make up for and differences.

I have towed 7k pounds with my v6 with 3.55s. It handles it pretty well all things considered and I can honestly say I feel ZERO difference between my old one with 3.73's.
 






I understand where you are coming from. My statement was meant as intended, that everyone will have to decide for themselves whether to stick to the ratings or not. Here are my responses to some of your points:

1. No vehicle manufacturer is going to tell you it's OK to change tire sizes at will, any more than they will advise you to change gearing at will. Just because a change in tire size can result in similar ratio changes does not mean that either is OK.

2. Talking about gearing in relation to velocity (mph) when cruising is great for discussion about gas mileage. In those terms, your points could be used to state that the differences in gas mileage with these gears is minimal (and the are!).
But my points are not for how things feel, or how efficient they are. As an engineer, I'm concerned about longevity and durability. And in those terms, you need to speak about gearing at low vehicle speeds (high engine load), like when starting from a stop. At these times, you put more stress on the drivetrain (engine, transmission, etc) with the 3.55 gearing than with the 3.73 gearing.

Over several years, that will be the difference in the 5-speed transmission making it to 100,000 miles....or not. Nobody is saying that pulling 20% over the rating is going to result in catastrophic failure on that trip, or even in this year. But you are doing more damage to the running bits when overloading the system like that, compared to sticking to the limits.
 






Excellent replies, all. I thank each of you for taking the time to respond. I would not usually drive a truck, much less a 4WD with extra gas consumption and mechanical things to maintain, year round for a task I will probably only do (camping) twice a year if that. This guy is my daily driver and used in a city environment exclusively. I had considered a full-size truck, but anything in my firm budget (18k or less) had at least 90-120k miles and were over 5 years old.

That said, when you find a wheelchaired man in assisted living that's ditching his car because he can no longer drive, and the thing has 13k accident-free miles on it, for $18k, you buy it and deal with the details as needed.

I looked for months for the right vehicle, with 18k as a hard limit on my budget, hoping to get at least some towing capacity as I do have an 8' cargo trailer I occasionally use.

If I truly need to change the diff, I am not beyond that, it's OK, it was on my radar. Rather, I am particularly concerned if I need to add extra oil cooling, or a larger (if fitted by Ford in the Factory tow pkg) transmission cooler, or larger brakes, etc. Something really necessary that I might not be so aware of. These days there is so much software control, I would not have been surprised to hear I needed a new controller for the trans, a motor ECM and a different ABS unit. I'm not hearing any of that here, and that makes me happy. As to the numerical examples given as the real-world differences between gear ratios, I think we need to also consider the torque converter stall, (the same for tow version? No idea on that) and what happens at lower speeds in the lowest gear, to the valid point of the Brakeman. On balance, I think I need to take the build sheet (I have it) to the Ford dealer and get him to tell me exactly all the differences included in the tow package, just to be sure. Then I can feel good about shopping for a lightly-used axle assembly. I just don't like surprises. I am, however, liking this vehicle more than I thought I would. Thanks again for taking time to comment here, it REALLY is appreciated, you guys are great. I am a firm believer in the power of public experience and really glad I found this forum to get some information on this. Additional comments welcome, please! - DanPaw
 






I understand where you are coming from. My statement was meant as intended, that everyone will have to decide for themselves whether to stick to the ratings or not. Here are my responses to some of your points:

1. No vehicle manufacturer is going to tell you it's OK to change tire sizes at will, any more than they will advise you to change gearing at will. Just because a change in tire size can result in similar ratio changes does not mean that either is OK.

2. Talking about gearing in relation to velocity (mph) when cruising is great for discussion about gas mileage. In those terms, your points could be used to state that the differences in gas mileage with these gears is minimal (and the are!).
But my points are not for how things feel, or how efficient they are. As an engineer, I'm concerned about longevity and durability. And in those terms, you need to speak about gearing at low vehicle speeds (high engine load), like when starting from a stop. At these times, you put more stress on the drivetrain (engine, transmission, etc) with the 3.55 gearing than with the 3.73 gearing.

Over several years, that will be the difference in the 5-speed transmission making it to 100,000 miles....or not. Nobody is saying that pulling 20% over the rating is going to result in catastrophic failure on that trip, or even in this year. But you are doing more damage to the running bits when overloading the system like that, compared to sticking to the limits.

I hear ya and by all means I don't disagree. Just from the engineers I have talked to and the research I have done I feel that the difference is more like a transmission making it to 95000 miles instead of 100000 and that to me personally is acceptable.

I should have added that on mine I added a trans cooler that is larger than factory tow package coolers to help account for some of the heat buildup from the added stress on the Trans.

The reason I mentioned tire sizes is because a lot of people put taller tires on and don't think about how much that changes the fearing and then then tow max capacities anyway (especially on pickups).

People don't go blowing transmissions all the time in those cases and I'm not saying they aren't wearing them out faster... Just putting it all into perspective that's all.
 






Back
Top