โJun-07-2017 04:27 PM
โJun-23-2017 05:02 AM
blackgrizz550 wrote:
...
I towed my camper with it for the first time last weekend. It did decide to kick down to second gearing while braking down a hill. 5,500 RPM's seemed a little excessive. Other than that, it worked fine. It likes 7th gear mostly while towing.
โJun-22-2017 11:00 AM
TurnThePage wrote:
I'm interested in more real time reviews of that 10 speed transmission. Everything I've read/heard so far doesn't make it sound all that awesome. Maybe just some fine tune programming...
โJun-15-2017 04:58 AM
time2roll wrote:
Anyone have a 2017 EPA number for 3.15 vs 3.55?
I cannot seem to find much where is ratio is called out.
โJun-15-2017 12:35 AM
time2roll wrote:
Anyone have a 2017 EPA number for 3.15 vs 3.55?
I cannot seem to find much where is ratio is called out.
โJun-14-2017 09:34 PM
โJun-14-2017 08:55 PM
Huntindog wrote:
It is a choice. Do you want better performance when towing? Or better MPGs when empty?
The different rear axle ratios WILL make difference. Neither choice is "wrong" or "right".
The 3.55 will have the effect of making it a close ratio trans... IOW, the motor will operate at it's powerband peak more. This will change the personality (so to speak) of the truck, and it will just make for a better tow, and probably a little better MPGs when towing. At the expense of sacrificing in MPGs when empty.
When deciding, you gotta consider just how much you tow, and how demanding your towing conditions are.. There is more to it than just looking at rpms @ a certain speed. How you get to that speed matters as well.
IOW, if you have two indentical trucks/trailers with only the rear axle ratios different. And drive them both.... One WILL impress you more. In this case, the 3.55 truck.
Unhitch the trailers, and the difference is mainly gonna show up as better economy for the 3.15 truck.
Your money. Your choice.
โJun-14-2017 02:45 PM
time2roll wrote:
So it is not entirely the transmission... Extra 12 percent torque makes a difference too.
3.55 to 4.10 is 15 percent.
Put both behind the same engine and the 4.10 to 3.55 is not as exciting.
โJun-14-2017 02:24 PM
time2roll wrote:ShinerBock wrote:The top gears for fuel economy are not a big concern to me. But to lose 4 of your gears all at the top seems poorly balanced. I would rather be in the middle 6 ratios for normal conditions. For economy I would have 2 more at the top, and for an unexpected steep condition have two more at the bottom. A lower 4.10/4.56 would present this flexibility. I would worry more about getting started on a 15+ percent incline more than a bit of economy.
So you expect to be able to use all of your gears in any situation when towing? I am not sure what your towing experience is and I am not trying to insult, but most vehicles are not able to use all of their transmission gears in every situation when towing heavy (or even moderate loads for some) regardless if the have a 5, 6, 8, or 10 speed transmission.
Most current 6 speeds have two overdrives which are 5th and 6th gears. With my 2014 Cummins, my 6th is utilized as my overdrive when unloaded and towing light loads for better fuel economy. I lock out 6th and use 5th as my overdrive when towing moderate to heavy loads on the highway. Again, for better fuel economy and to keep the EGT's in check.
Just because you have all those gears, doesn't mean you have to use them in every situation. They are there to keep the engine in its power band and have enough torque multiplication to keep the vehicle moving forward. Heck, even tractor/trailers with 13 or 18 speeds are not able to use all gears in every situation when towing.
I understand those tractor/trailers don't always use the lowest gear to get moving. Or do they?
โJun-14-2017 02:18 PM
โJun-14-2017 02:09 PM
time2roll wrote:
The top gears for fuel economy are not a big concern to me. But to lose 4 of your gears all at the top seems poorly balanced. I would rather be in the middle 6 ratios for normal conditions. For economy I would have 2 more at the top, and for an unexpected steep condition have two more at the bottom. A lower 4.10/4.56 would present this flexibility. I would worry more about getting started on a 15+ percent incline more than a bit of economy.
time2roll wrote:
I understand those tractor/trailers don't always use the lowest gear to get moving. Or do they?
โJun-14-2017 01:32 PM
atwowheelguy wrote:It is a choice. Do you want better performance when towing? Or better MPGs when empty?
With my '13 F150 3.5 EB 3.55 having just surpassed 100k miles, I started glancing at what's available these days. It is my only caged vehicle, I haul grandchildren, I occasionally need to squeeze it into a parking deck, and I tow a toy hauler that at various times weighs 6600-7200 lbs. Therefore the 3.5 EB Supercrew 5.5 ft. bed 145" wheelbase configuration is the one that best fits my needs.
I notice that for '17, only two axle ratios are available for that configuration with the 3.5 EB, the 3.15 and the 3.55. In '13 it was available with four axle ratios: 3.15, 3.31, 3.55 and 3.73. I ended up with a 3.55. The spread from 1st to 6th on the six speed is 604%. The spread from 1st to 10th on the ten speed is 744%.
I also note that the GCWR for my '13 3.55 six speed is 15,300 with a max trailer of 9,800, whereas the GCWR for the '17 3.15 ten speed is 15,800 with a max trailer of 10,700. The advantage is the 10 speed transmission in the '17, plus the '17 has a little more power. They have almost the exact same first gear final drive ratio.
My current wet and loaded camper weighs 6,640 (68% of 9,800 max trailer) which results in a GCW of 12,500 (82% of the GCWR) and the '13 tows it with no sweat. It's at 94% of GVWR, having used up 71% of its payload. I'll be looking at the 3.15 axle with the 10 speed for the next one to tow as well as the 3.55 six speed and get a little better highway mileage when not towing (19% fewer revs per mile in high gear). I give the Ford engineers an "attaboy" for this one.
โJun-14-2017 01:08 PM
ShinerBock wrote:The top gears for fuel economy are not a big concern to me. But to lose 4 of your gears all at the top seems poorly balanced. I would rather be in the middle 6 ratios for normal conditions. For economy I would have 2 more at the top, and for an unexpected steep condition have two more at the bottom. A lower 4.10/4.56 would present this flexibility. I would worry more about getting started on a 15+ percent incline more than a bit of economy.
So you expect to be able to use all of your gears in any situation when towing? I am not sure what your towing experience is and I am not trying to insult, but most vehicles are not able to use all of their transmission gears in every situation when towing heavy (or even moderate loads for some) regardless if the have a 5, 6, 8, or 10 speed transmission.
Most current 6 speeds have two overdrives which are 5th and 6th gears. With my 2014 Cummins, my 6th is utilized as my overdrive when unloaded and towing light loads for better fuel economy. I lock out 6th and use 5th as my overdrive when towing moderate to heavy loads on the highway. Again, for better fuel economy and to keep the EGT's in check.
Just because you have all those gears, doesn't mean you have to use them in every situation. They are there to keep the engine in its power band and have enough torque multiplication to keep the vehicle moving forward. Heck, even tractor/trailers with 13 or 18 speeds are not able to use all gears in every situation when towing.
โJun-14-2017 12:34 PM
โJun-14-2017 12:06 PM
time2roll wrote:ShinerBock wrote:Don't just compare low gear.
OP, nice data.
I only hope that it gets through to some of these hard headed old timers that are stuck in their "shortest gear is needed" ways of thinking.
Looking at about 4:1 for actual cruising you lose the top two gears with the 6 speed and the top 4 gears with the 10 speed. If you pay for a 10 speed but can only use 6 when towing I just don't see the point. Put 4.10/4.30 in there so I can use 8 of the 10. Who needs 4 OD gears for fuel economy? Yes EB run at lower RPM but still.
JMHO