Airstreamer

I have a 2012 F150 XLT Supercrew 145" WB with 3.55. That results in a 7,700# tow rating and 13,500 GCWR. My same truck with the 3.73 would raise the tow rating to 9,300# and GCWR to 15,100#.

Based on that I'm fairly confident that the frame, brakes, and suspension are up to the task for 9,300# and 15,100# on my truck despite the lower ratings. Would that be correct?

What then is the limiting factor? Transmission cooling ability? What about starting in 1st gear? Is that the limiting factor?

I run pretty close to the 7700#/13,500 GCWR limit fairly often and when I do I routinely lock out 6th gear to keep my RPM's in the 1800-2000 range, which feels much better than the 1400-1500 RPM's resulting from 6th gear. It also reduces the amount of shifting on small inclines.

I trust this is "protecting" my transmission from heating up too much. Also putting less stress on the engine.

So if I do this can I safely run at/exceed the 7700# tow rating? Is that mitigating any damage that might be done to my truck?

Nighthawk87

Sure. I agree with what you've said but the problem is you aren't legally able to tow that weight. If you get in an accident whether it's your fault or not, it will be blamed on you. Worse yet, if someone dies then it's going to be blamed on you for negligence.

Airstreamer

Thanks. I appreciate that. While I'm close to the 13,500 GCWR, I do stay below it.

I guess the question boils down to "what component is the limiting factor requiring the 3.55 to be limited to 13,500 GCWR from 15,100 GCWR of the 3.73?"

zx12-iowa

Look at a dodge forum or a ridgeline forum. Those guys routinely two 20% over limits with zero issues. So your truck is fine.

Velosprout

The 3.73 allows the truck to do more work by multiplying the torque. Liken it to riding a 10-speed bike. You might not be able to ride up a steep hill in the 10th gear and end up walking. In the lowest gear you are able to climb for miles. Your lungs, legs, and heart are not the limiting factors, just the gearing. Likewise it is not the transmission, engine, or brakes limiting your towing, but the gearing.

Changing gearing does not change the posted limitations of your truck. Trading trucks is the safe and cost effective solution.

Can you tow 20% over without ill effects? Probably, and for many miles. You can also overfill your crankcase oil by 20% and go 20% longer than recommended for oil changes. You can over-inflate your tires by 20%. None of these choices are wise, however. Both for your safety and truck longevity.

11screw50

Lots of people throw the legality card out there but I have yet to see anyone show a law that limits one to the manufacturer's recommendations. (Not saying that exceeding the manufacturer's recommendations is a good idea or that it should be done but from the towing laws I've seen, most states have limits that would break our trucks before we even got close). And the Feds only seem to regulate commercial, interstate vehicles.

And just because I have not found such laws does not mean that they do not exist. Safe bet is to stay below the limits as stated by the manufacturer.

Airstreamer

I'm an avid cyclist so I view this the same way. Isn't my locking out 6th or shifting to an appropriate gear going uphill effectively putting me in a similar gear ratio as the 3.73 so long as I have that available? For example, my 3rd gear might be close to the 3.73 4th gear, and so on.

Still, there are at least three scenarios where I couldn't compensate:

1. If I lock out 6th and go really fast, such that the truck hits red line and I "run out of gears" to reach a higher speed. This is not something I'm worried about at all. I try not to exceed 65 towing and regularly run at 60.

2. My 1st gear ratios are too tall for the weight of the trailer. This I would have no cure for because I don't have a lower gear. Is this a real issue? One of the reasons I'm asking, but I tend not to think so.

3. Going downhill I select too high a gear and do not get good engine breaking to slow my combined rig. This also is not something I'm particularly worried about as I manually select a lower gear. Could I run out of gears when I hit 1st, I suppose so. But that would be a big hill.

At the end of the day, I tend to think the 13,500# vs. 15,100# ratings are most related to my point 3, to account for the inattentive driver that would go down a high % grade in 6th gear. The 3.73 might have enough compression to slow the rig in 6th whereas the 3.55 might not?

At some point I will likely be buying a new truck so I have a bigger buffer between the ratings and my actual weight, but I do have to say that my truck handles the trailer quite well. The only thing I added were LT tires instead of the stock P rated tires. That knocked out what squirmy-ness there was. I obviously also use a WD hitch with sway control.

Not to derail my own thread, but for towing a 7,000-9,000# trailer with enough payload for cargo, I would love Ford to come out with an F-250 with a larger ecoboost or a smaller diesel. Nissan tried but that looks like a swing and a miss... My best current bet would be an F150 with HD towing and payload packages or a well selected XLT that would probably exceed 2000# payload. My current truck is just over 1600#.

smokeywren

GCWR and tow rating are not your limiters as to how much trailer you can tow without being overloaded. Ignore that stuff and concentrate on GVWR and payload capacity. You will run out of GVWR and payload capacity long before you get close to the GCWR and tow rating.


If you tow a wagon-style trailer with almost no hitch weight, then you can reach the 7,700 tow rating without exceeding any of Ford's weight limits. But ignore the tow rating and use the GCWR. (Tow rating = GCWR minus truck weight). GCWR is a firm engineered number, but tow rating is an unrealistic wish.


If you exceed the GCWR, then the primary ill effect is the power and torque required to climb ills and mountain passes. You'll probably be the slowpoke holding up traffic.


The GCWR tells you the max combined weight you can have without overheating anything in the drivetrain.


The first component to overheat will be the automagic tranny. Your XLT does not have a digital tranny temp gauge, so you have to rely on that idiot gauge on the dash. That gauge does not work the way you might think. The normal zone means you're good to go, but the instant it jumps from normal into the yellow zone your tranny is too hot, If you ignore that tiny yellow zone, then the instant it jumps into the red zone means your tranny is probably already toast. So when towing up grades, or towing in rush-hour traffic at less than about 45 MPH with an unlocked torque converter, you have to watch that tranny temp gauge like a hawk. And the instant it jumps into the yellow zone, pull over and stop. Leave the engine running and elevate the idle to 1,200 RPM, then sit there twiddling your thumbs until the gauge jumps back into the white (normal) zone.


If it ever jumps into the yellow zone, then change the ATF to full synthetic the first opportunity, and then continue to change it every 20,000 towing miles. Also to prevent it occurring again, replace the oil-to-air tranny cooler with a much bigger heat exchanger.


And if it's me, I'm going to install a real tranny temp gauge with the sender in the lower side of the sump (tranny pan). You don't need digital, but an analog gauge must have clear markings around 220° or 230°. 225° is the redline for tranny sump temp.
http://www.issprogauges.com/v/vspfil...-R13533-2T.jpg

Airstreamer

Yea, I've quickly learned that payload is where there are the most problems according to the numbers. I have to get back to the scales, but based on my estimates I'm good. My trailer has a tongue weight of around 900# and my truck has a payload of over 1600#. I don't run anywhere near 700# of occupants and cargo.

And my truck does have a digital temp gauge. I tow mostly on the east coast so we don't have crazy long grades. Highest temp I recall seeing was probably 210-215 degrees. I think I'm OK in that range. It runs to almost 200 degrees without the trailer.

Blackpony

Can you safely tow it? Yes
Is it hurting the truck anymore then one with 3.73? Absolutely not
Is it legal to do so? Technically no
Do people do it on a daily basis with no Ill effect? Yes

I have towed well over 10k with my old regular cab that was rated at 8300 and did I see any ill effect? Absolutely not, and as a matter of a fact it handled the weight a lot better then my current super cab does. Honestly I would rather be in that truck towing anything over 6-7k then my current truck. It seemed to have a lot more power, no issue stopping with the factory tbc, the fuel mileage was leap years better etc. that truck had 3.31 gears my current has 3.55 gears.

As stated do at your own risk but know that it is not and will not hurt the truck anymore.