6R80 Gear Ratios and Specs

Most people look up 6R80 gear ratios for one of two reasons. Either they are running the numbers on a gear swap, a tire change or a towing setup, or they have a scan tool on the truck and a gear ratio code on the screen and want to know what the transmission is supposed to be doing. This page is written for both. The ratio chart is at the top. Below it is the part that actually helps on a repair: which clutches make each ratio, which solenoids command them, and how to use that to find the failed clutch before the pan comes off.

The 6R80 is Ford's version of the ZF 6HP26, and it kept the ZF gear set. The ratios below match the ZF 6HP26 data sheet exactly [1], and the clutch apply logic comes from ATRA's apply chart for the 2011-up 6R80 [2].

Recommended 6R80 parts

When the ratio math points at a slipping clutch or a solenoid that is not commanding it: the master rebuild kit, a replacement clutch module, and a full 7-piece solenoid set. Secure checkout.

6R80 Transmission Master Rebuild Kit, Ford F-150 Expedition Mustang

$383.99View part

6R80 Clutch Module

$222.99View part

6R80/6R60 Transmission Shift Solenoid Set, 7-Piece Ford

$153.99View part

6R80 Gear Ratio Chart

Here is the full ratio set, the step between each gear, and the two elements that are applied to make each one. The step column is simply one ratio divided by the next; it tells you how far engine RPM drops on each upshift at a given road speed.

Ratios are from the ZF 6HP26 type sheet [1]; applied elements are from ATRA Technical Bulletin 1861 [2]. The steps are tight at the top and wide at the bottom, which is what you want in a truck: a deep first gear to get a load moving, then closely spaced upper gears so the engine stays near its torque peak on the highway. That 1-2 step of 1.78 is the biggest RPM drop in the box and the shift that gets the most attention in calibration.

Where the Ratios Come From: the Lepelletier Gear Set

The 6R80 does not have six separate gear sets. It has two. ZF's own data sheet describes the 6HP26 as based on the Lepelletier gear set concept [1]: a simple planetary in front and a Ravigneaux (compound) planetary behind it. GEARS Magazine's David Chalker breaks the 6R60/75/80 down the same way: a four-element torque converter with a multi-disc lockup clutch, three driving clutches (A, B and E) and two brake clutches (C and D) [3].

The front planetary is a fixed reduction. Input drives it, and its output turns slower than engine speed all the time. The A and B clutches take that reduced speed into the rear gear set. The E clutch takes full input speed straight into the rear gear set. C and D are brakes that hold members of the rear set to the case. Pick two of those five and you get a gear:

• 3rd gear shows the trick most clearly. With A and B both applied, both sun gears of the rear set turn at the same reduced speed, the Ravigneaux set locks up and turns as one piece, and the output runs at the front planetary's reduction. That is why 3rd is 1.52:1: it is the front gear set's ratio passed straight through.
• 4th through 6th all use E, which means the rear set's carrier is being driven at engine speed. Pair it with A (4th), B (5th) or the C brake (6th) and the output speeds up relative to 3rd, until 5th and 6th turn the output faster than the input. Those are the two overdrive gears.
• Reverse uses B and D. B drives the rear set at reduced speed while D holds the carrier, and the output turns backward at 3.40:1.

Ford names most of these clutches by the gears they work in, and you will see both naming systems in service information. Sonnax's 6R80 shift-quality article uses the Ford names: the 1-2-3-4 clutch is on in 1st, the 2-6 clutch comes on in 2nd, and on the 2-3 shift the 3-5-R clutch applies as the 2-6 releases [4]. Map them over and A is 1-2-3-4, B is 3-5-R, C is 2-6, D is low/reverse and E is 4-5-6. Every letter lines up with the chart above.

The 2011 One-Way Clutch Changed First Gear

First gear is the one ratio that is made two different ways depending on the year. In 2011 Ford added a one-way clutch to the rear planetary assembly. Chalker writes that it was designed to provide smoother 1-2 and 2-1 transitions, quicker downshifts and better fuel economy [3]. ATRA's bulletin spells out the apply change [2]:

• 2009-2010 units: the D clutch applies throughout first gear.
• 2011-later units: the D clutch applies only until about 3 mph, then releases, and the low one-way clutch holds for the rest of first gear.
• Manual 1st (all years): A and D are both applied, which gives you engine braking in first. The one-way clutch alone cannot do that because it freewheels on decel.

That split is a useful diagnostic. On a 2011-up truck, a slip or no-move in Drive first gear that goes away when you select manual 1st points hard at the one-way clutch, because manual 1st brings D back in to do the holding. The 1-2 shift on these units is also no longer a clutch-to-clutch swap; the one-way clutch overruns as C applies, which is exactly why Ford added it.

6R80 Solenoid Apply Chart

The ratios only happen if the solenoids put pressure on the right clutches. ATRA's chart for the 2011-up 6R80 lists five shift solenoids, the pressure control solenoid and the TCC solenoid, each marked normally low (NL) or normally high (NH) [2]. An "X" means the solenoid is at high duty cycle, about 850 mA; no X means low duty cycle, about 50 mA [2].

The pressure control solenoid (NH) is modulated by load in every range, and the TCC solenoid (NL) is modulated in 2nd through 6th [2]. Reading this chart takes one rule that ATRA prints right under it: a normally low solenoid is proportional, so high current applies its clutch; a normally high solenoid is inversely proportional, so high current exhausts its clutch [2]. Look at 3rd gear: SSB has no X, it sits at 50 mA, and because it is normally high that means the B clutch is fully applied. In 4th SSB goes back to 850 mA and B releases. If you watch commanded solenoid current on a scan tool, this is the chart you check it against.

Two more things matter when you are replacing solenoids to fix a ratio problem. Sonnax's identification guide notes that 2010-later Ford solenoids are cream-colored and carry a flow band number from 1 to 5 [6], and the PCM's solenoid body strategy is written around those bands. We cover band matching in detail in the 6R80 pressure control solenoid guide.

What the Ratios Mean on the Road

The transmission ratio times the axle ratio gives you the overall ratio at the tire. A few worked numbers with a 3.55 axle, which is a common F-150 choice:

• 1st: 4.17 x 3.55 = 14.80:1 overall
• Reverse: 3.40 x 3.55 = 12.07:1 overall
• 6th: 0.69 x 3.55 = 2.45:1 overall

For cruise RPM, a 31.5-inch tall tire turns about 640 times per mile (63,360 inches in a mile divided by the tire's 99 inch circumference). At 70 mph that is about 747 tire RPM. Multiply by the 3.55 axle and the 0.69 sixth gear and you get roughly 1,830 engine RPM with the converter clutch locked. Drop to 5th and the same speed is about 2,310 RPM. That difference is why a truck towing in 5th on the highway runs noticeably hotter fluid and louder than one that can hold 6th, and it is the math to run before you put taller tires on a truck and wonder why it will not stay in 6th.

If you change tire size, the speedometer and the PCM's idea of road speed change with it. The transmission ratios do not, but shift points that the PCM schedules by vehicle speed will land in different places until the tire size is reprogrammed.

Using the Ratios to Find a Failed Clutch

The PCM checks gear ratio by comparing input (turbine) shaft speed to output shaft speed. If the measured ratio does not match the commanded gear, it sets an incorrect ratio code: P0731 (1st), P0732 (2nd), P0733 (3rd), P0734 (4th), P0735 (5th), P0729 (6th), P0736 (reverse), or the general P0730. You can do the same math yourself: divide the ISS reading by the OSS reading in each gear and compare it to the chart. A slipping clutch shows up as a measured ratio higher than the commanded one, because the input is turning faster than the output says it should.

The real value of the apply chart is that most clutches work in more than one gear. Line up the gears that slip, find the clutch they share, and you have your suspect before you tear anything down:

A pattern that does not follow one element, such as slips in every gear, points away from a single clutch and back toward line pressure, fluid level, the pump or the converter. The standard rule in 6R80 diagnosis is to fix non-transmission codes first; a torque-reporting fault changes commanded line pressure and can make healthy clutches slip. For the full P0730 procedure, see our 6R80 P0730 guide.

Other 6R80 Specs Worth Knowing

A word on that ZF row: those are ZF's published numbers for the 6HP26, not a Ford rating for the 6R80, and they are listed so you can see where the design started. Ford changed a lot after 2006. Transmission Digest's Mike Riley notes the 6R60 came first, then the 6R75, and the 6R80 was built to handle higher torque, with pump, stator support and forward clutch piston changes along the way [8]. Sonnax counts four separate 6R80 design levels between 2009 and 2017 [6]. The ratios stayed the same through all of it; the hard parts did not. Always identify the unit before you order parts. Our 6R80 identification guide walks through the casting numbers and tag.

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