I am in the market for a new truck and I will admit to being a long time gm owner and fan, however I love the new super dutys. They look amazing and gms gas engines are a bit lacking in the towing department and I do not like the new body style. My question is this, I noticed the ford and gm six speeds do not have a direct drive ratio, so that leaves me either in an under drive ratio or overdrive ratio when towing. How is this optimal? Do the gas engines have enough to move a relatively heavy(15000-20000#s) in overdrive? I absolutely do not want a diesel. They are nice and strong and I can afford one but I just refuse to pay what they are asking for one not to mention repair and maintenance costs. I live in louisiana so hills and grades are not an issue for me. Thanks for any feedback. For reference my current ride is a 1997 320000 mile gmc 2500 with a 350 4speed auto and 3.73 gears. Yes I keep them a long time!

 

You can go as high in the gears as you want and stop there. Manuals are no longer offered after 2010.

 

I am aware it's an automatic I just don't quiet understand the lack of a 1:1 ratio in the transmission. For example in my current set up I just put the trans in 3rd when pulling heavy. Third is 1:1. On the new transmissions there is no 1:1. From what I have read the 6.2 pulls fine. I guess I don't understand how they can pull heavy in overdrive which leaves 4th gear which is under driven which seems a bit excessive rpm wise. Does anyone know the reason the manufacturers skipsd a 1:1 ratio?

 

i hesitate to post this because it is a video of how GM's 6L80 works. however, the 6L80 and ford's 6r80 are both made under ZF's license, with only minor differences in the gear ratios.

the 6r140 works on the same principle, so that's why i'm posting it.

the answer to your question can be seen in the video, but the short version is "that's just the way it works". there are essentially 3 planetaries within the transmission, two of which are housed in the same carrier at the rear of the transmission.

4th, 5th, and 6th gear is obtained by running the front planetary through the rear planetaries in differing combinations. by doing so, you are always running an under driven gear (3rd) through an overdriven gear (4th, 5th, 6th), to end up with a final drive ratio.

the video explains it much better than I am. and if you watch it about 10 times, it actually starts to make sense.

 

Not real sure about ratios and such, but I pull a 33' gooseneck, 4 horse, 10' living quarter with mine, I put in tow/haul, and let'er roll! Took this from east Texas to Georgia and was more than pleased.
Crew cab 4x4 f-250, stock gas rig.

 

You may want to go over to the 6.2 forum for more information on towing with the F-250/6.2 gas. RVpuller is towing a 16K trailer with his and seems to be very happy. I have a 2013 F-250 w/3.73 axle towing a 11-11.5K travel trailer. I am extremely happy with my truck. Can not get into all the particulars of how it works, but you can just put this truck in tow/haul mode, lockout 6th gear and let her roll. I also live in East Texas and have not traveled in extremely hilly area.

Ray

 

I don't understand your fascination with a 1:1 ratio. The 6R140 is a strong transmission with these ratios:

First - 3.97:1
Second - 2.32:1
Third - 1.52:1
Fourth - 1.15:1
Fifth - 0.86:1
Sixth - 0.67:1

Why would the lack of a 1:1 ratio matter?

 

It's not that I have a fascination with a 1:1 ratio, I guess I was under the impression that direct was the most efficient means of transmitting power to the rear axle when pulling. In overdrive you loose torque multiplication to the rear axle and under drive is not as efficient as a direct drive at a steady speed. I am just used to old school set ups like my current truck which will not pull my tractor and trailer in OD, but pulls just fine in direct. Of course I am aware of the extra power these new trucks have and I am just trying to learn more about the product.

 

direct drive is always more efficient than any gear with a ratio. running in any gear other than 1:1 will always create more heat than a 1:1.

BUT

it seems to be a non factor, as the gearsets on the new transmissions seem to be very efficient in operation.

in these transmissions it would appear that 3rd is the simplest gear in which to operate, and 4th is likely the strongest.

BUT

i wouldn't worry about it.

it takes some getting used to, but the idea of not pulling in overdrive is antiquated thinking. in all reality, you can just drop it in drive and go 90% of the time and the truck will sort it all out for you. IMO, anyway.

 

With a manual transmission 1:1 does lock the input shaft to the output shaft directly, so by not going through any gears it is indeed more efficient. Automatic trans are putting every gear through a planetary gearset, so no difference in efficiency to speak of. I agree with "drop it in drive and go" - my 5r1100 doesn't even have a way to block out fifth gear. I think the new automatic transmissions are pretty amazing compared to the old-school 4 speeds.

Brian

 

First off, welcome to the FTE forums. I admire your courage in admitting to be a long term GM fan, especially when coming to a Ford website.

I also understand where you're coming from about being "old school" about trucks. My last truck was a 74 Dodge Powerwagon. There's just no comparison between new and old technology when looking at trucks.

I can't get into specifics on the trans either, but we did have a thread I think in the 6.2 forum from the actual Ford engineer(s) that designed the 6.2 engine. They stated as far as the transmission was concerned, they spec'ed out the gear ratios to be optimum for the 6.2's operating range for both power and economy. I think that has more to do with "why" you don't see a 1:1 ratio in it.

I think the ratios we do have fall in line together very well. There's no drop off in power from one gear shift to the next through any of the gears 1-6. Very happy with my truck after 15 months and almost 10k miles.

If my forum "mojo" was better, maybe I could find that old engineering thread, but it's a good read if you can locate it.

I'm more than pleased with my own 6.2 truck. The heaviest trailer I've pulled so far is an 8K gross that it pulls with ease. We do have rolling hills here, but no mountains. At most I would have to lock out 6th, but mostly I just put it in tow/haul and set the cruise control and let her buck.

If I drove through mountains, I'd probably lock out 5th and 6th, and maybe use the manual mode for the truly steep portions.

 

I wouldn't get too hung up on the ratio, it's only a number. A ton of engineering research, testing, and real-world evaluation went into the picking of the ratios for each gear. One must consider the engine's dynamics as far a torque and horsepower curves for matching to the most optimal ratios.

I just bought a 2014 6.2L gasser to replace my 1987 F150, so I keep my trucks a long time as well. I love the 6.2 even though it does have a little lag between gears, and as many have said on here it loves RPMs. Looking at a tuner by 5 Star.

Good luck and welcome back from the "dark side"......

 

Thanks to everyone for the replys and feedback. I have been an fte member for a couple of years now but I usually hang out on the older truck section as my other truck is a 51 ford 2 ton. Thanks for welcoming me to the newer truck side. I am pretty excited a out getting a new truck and love doing the research andearning the ins and outs of these newer trucks. Not only do I like driving but my mechanical mindset allows me to enjoy how they work and why they are made the way they are. The ins and outs of the drivetrain and how they work together

 

Indeed the 1:1 straight through ratio is the most efficient, but when the transmission is under the heaviest load (fully loaded truck climbing a hill) chances are you are going to be in a lower gear regardless of whether or not it's a auto or a manual tranny.

Where the 1:1 is great was way back when the wife and I were dating she had a '76 chevy monza that grenaded it's tranny, the only gear that would still move the car was fourth and she drove it like that for weeks.

-Joe

 

that's not entirely true.

in order to achieve a 1:1 in an automatic, the entire planetary is spinning, but the power is not running through the planetary gearset.

with the 6r140, in 4th, 5th, and 6th, the power is actually going through TWO sets of planetary gears, so there is going to be some mechanical losses, but as i said, if it was an efficiency problem, they wouldn't do it that way.