The gears aren't that much different in the 6r. 1 extra od and a really short first gear.I would imagine the gain being in drivability. There is a huge drop between 3rd and 4th gears; in the 40-60 mph range you have to either keep 4th locked out, or deal with the huge drop in rpms, especially at lower speeds, between those two gears. Having another gear here and there would make the L so much more pleasant to drive.
Some of us don't like spinning the motor for no reason and drive the highway a lot. 75mph is a lot of rpms.I turn the OD off on my truck as soon as it's running. Don't turn it on unless hitting a highway or turnpike. I don't miss the extra gears at all. Have a five speed in my Mustang, I still turn the OD off as soon as it's running.
The Coyote and EcoBoost like to rev. They can handle more gear. The Lightning doesn't. Not at all. It revs like a diesel. You need to keep the rpms down and in the mid range.I heard people say the 6R80 and 10R80 are geared to aggressive for our trucks powerband, but I don't see TVS/Whipple/KB Coyote and F150 guys complaining even with 3.55's or 3.73's.
10r80s are struggling to live at big power. Add the weight of a truck and it gets worseI say source out a 10R80. Then go with the least aggressive rear gear for a 9.75". Your highway driving will be 3x better. The 4R100 1st gear is too tall, and it's too quick to shift out of 1st particular when making a left turn and that kills to power until you van build some RPM's. These newer transmissions are so much more willing to downshift than your old 4 speeds.
I heard people say the 6R80 and 10R80 are geared to aggressive for our trucks powerband, but I don't see TVS/Whipple/KB Coyote and F150 guys complaining even with 3.55's or 3.73's.
See it's the other way here. I'm very rarely under 55I turn the OD on when on the highway. Didn't you read the whole post. It's only off for in town and city driving. Mostly 35 to 45 mph speed limits where I live. If I hit a 50 mph zone and will be on it for a distance, OD on. It's just, most of the time, it's simply not needed here. I don't do a lot of highway and turnpike driving. Very rarely.
The od on the 6r and 4r are almost identical. I posted themThat's why I would go with a conservative rear gear. If I'm not mistaken a 6R80 and 10R80 use like a .62 or .65 final overdrive as opposed to the .71 overdrive gear in the 4R100. The 4R100 was meant to be used on a 7.3L PSD and it's gearing is far from optimal for even a long stroke 2V torquer like a L's motor. It was used because it's what John Coletti had available to use in the late 90's that would handle 360 HP/440 lb-ft and not be a warranty nightmare for Ford. If the modern transmissions where available 20+ years ago then the L would have gotten one. The 4R100 is one of my least favorite things about the L. IMO it really hold back the trucks potential
BTW Ecoboost is far from an RPM motor. If I remember correctly it's peak power happens around 5,000 RPM and it redlines at 6,000 RPM's.?.?.?
I've heard that the 6 speeds are better for modding high HP with, but high HP with a 5.4L 2V is pretty tame by Coyote standards. (Even though we do make impressive torque when modded) Other than that the 10 speed is supposed to be a much better tranny.10r80s are struggling to live at big power. Add the weight of a truck and it gets worse
That's crappy. The 10 speed has a bit better 10th gear IMO. Still the more aggressive gearing will allow for a shorter rear gear as you have already said, and that would equal it being a better highway cruiser.The od on the 6r and 4r are almost identical. I posted them