KAM Reset – How often and when to reset it.
Here's another Oz-nology for you guys to start off the week. As I was replying to a customer email this morning, I realized that the information in the email could be useful for others, and decided I'd post it here for everyone's benefit. Going to try to post this in a way that makes it easy to read with the customer's questions/concerns followed by my replies.
All right…. Let’s unpack all of this, but first – stop resetting KAM. You’re not helping anything by resetting KAM. It’s only necessary after initially loading your tune. That’s why it’s only mentioned once in the instructions. If you were supposed to reset it frequently, it would have been mentioned in the instructions. You also don’t need to avoid WOT for 16 drive cycles. Again, follow the instructions – “drive the vehicle how you would normally but try to avoid WOT shifts for the first 10-15 miles.” It doesn’t say “avoid WOT for 16 drive cycles”. Right? There’s no need to read between the lines here. The instructions are very clear. Just follow them without modifying or adding anything, for best results. I’ll address the concerns from the original email, in order, below.
On any initial start, the transmission hangs in first gear. When leaving from a stop, the truck builds revs, then hits a spot where it feels the throttle input creates little to no progress, then bangs into second gear. It only appears to happen when the truck has been off for a period of time, such as the first start in the morning or after sitting for several hours.
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That’s pretty common for 10R80 transmissions. They use ULV (ultra-low viscosity) fluid and they are the only automatic transmissions, currently, produced that uses this type of fluid. The fluid doesn’t reach ideal viscosity until 180*F, which is why all 10R80’s have an internal thermostat regulated at 190*F. Anything below 180*F and the fluid is more viscous than intended for ideal transmission behavior, and can suffer from random “spikes” in internal pressures and cause hard or even slipping shifts. There’s really not much that can be done for behavior outside of the correct operating temperature, and I suppose it’s the trade-off for having a transmission that manages heat well, provides excellent performance, and is fairly robust. If the transmission is performing properly when at operating temperature, that’s the best that anyone can do, Ford included. You never felt it on the stock tune, because Ford skips the 1-2 shift in that range and goes directly 1 to 3. Maybe they did that for this reason, but, either way, it’s not hurting anything. On my personal 10R80 vehicles (and I’ve owned 5 different 10R80 equipped vehicles) they have all done this to some degree. My solution has been to either allow the vehicle to idle for 10-15 minutes before driving it, or if I can do that, I just manually click the first 1-2 shift when cold, and it’s fine after that. Some F150 customers report that putting the truck in Tow-Haul when cold helps as well, but it’s not something I’ve personally tried. Alternately, I can put the skip-shift programming back into your tune, but most everyone dislikes the skip-shift function and the “hiccup” you’re feeling when cold isn’t causing any harm to the vehicle. So, it’s up to you.
On 4-3 downshifts, the transmission occasionally bangs into gear. I am unsure if it's the downshift or converter.
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This, along with pretty much everything else you’ve mentioned is all going to come down to transmission adaptives. Anytime you use the words like “occasionally” when describing any function from the transmission automatically tells me that the transmission is still adapting. Why? Because computers are logic devices. Meaning, they perform the same function when that function is called. In simple terms, for a computer 2+2 will always equal 4. So, the PCM (the tune) is always commanding X. Now, what isn’t consistent are the mechanical components that the PCM is actuating. So, even thought he PCM is telling the transmission solenoids “perform X”, the solenoids themselves might be delivering X+1” or “X-1”, etc. The mechanical output is not perfect, the code is, and that’s why transmission adaptive learning was invented. There is a very complex control logic that consists of several PID loops (PID stands for Proportional-Integral-Derivative) which is essentially a control logic that allows the system to self-learn based on measured error after completion a specified command. In total there are roughly 560 different possible Shift IDs in the 10R80 control logic. A shift ID is what the logic uses to track a certain shift based on dozens of different factors. There are more than a dozen shift ID’s for the 1-2 shift alone. Some of those factors are based upon which Drive mode is active. Others are based on whether the vehicle is in a “Power-On” or “Power-Off” state. Others related to whether the vehicle is perceived to be climbing and incline or descending a decline. Other relate to is the steering wheel angle is above a certain degree of rotation, and these are just a few of the possible variables that the logic uses to define a Shift ID. The vast majority of these Shift ID’s do not have individual control tables, and they are instead based on interpolating between several of the base tables that are defined in the calibration. So, for many of those shift ID’s there are several tables that need to be adjusted and adaptive based on the feedback from the adaptation logic so that each portion of those tables that are used will reach the ideal target for the desired shift behavior. As you can imagine, this requires an enormous amount of data collection on the PCM’s part, and that data isn’t always 100% accurate. For example, imagine that you are driving on a damp road and the transmission shifts from 3rd to 4th gear right when you travel through some standing water, and one of the rear tires loses traction and spins momentarily. The adaptive logic has no way to know that you just passed through standing water and that’s what might have influenced whatever error might have occurred during that shift. So, it’s going to store that error in the adaptive logic functions, and next time that specific shift is called upon, the logic is going to command the shift, applying that previously learned error, and chances are good that the shift command will be over-corrected and there will be error measured in the opposite direction. This is just how the system works, and why adaptive functions are continually active whenever the vehicle is being driven. Eventually, the errors will reach near-zero and transmission behavior will become more consistent, but there will still be times when the logic may learn an incorrect error and over-correct because of that error. It’s an imperfect system, but it’s the best way to account for things like manufacturing differences in internal tolerance and clearances in the transmission, and also how the system can account for normal wear and tear from driving the vehicle as it accumulates mileage. These adaptive logic systems are the main reason why transmissions commonly last more than 100k miles in modern vehicles, where previously it was not uncommon to need to rebuild a transmission after 30-50k miles, especially in early automatic transmissions. So, the logic works very well, so long as you let it do its job.
All upshifts, but especially 3-6 when in "D" feel "jerky." Part throttle, normal driving causes the truck to jerk forward and "rock" momentarily on upshifts. The same behavior exists across all gears when manually shifting in "M"
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This goes hand in hand with the response above. You just need to drive the truck. Don’t baby it. Don’t avoid WOT. Just drive it however you normally would drive it. Babying the truck or avoiding certain driving situations is limiting the data that the adaptive system uses to learn. If you limit the data to the system, the less it’s going to learn. We include the note about not going WOT for the first 10-15 miles, not because doing so is going to cause any sort of issues, but because if you load your tune, reset adaptives, and then immediately go out an do a WOT pull, chances are very good that those WOT shifts will feel VERY firm or “off” for lack of a better term, and this would be especially true on a higher mileage vehicle. Nothing would happen, negatively, to the vehicle, but we would get tons of emails from customers thinking that something was wrong with their tune because of the way those first shifts felt. In reality, what would happen is the adaptive logic system would measure, what would likely be, a considerable amount of error, and it would immediately store that data to apply as a correction for the next time those particular shifts were commanded, and the shifts would likely feel much better. However, the average person does not have any knowledge about how these systems work, and the behavior of those first shifts would likely be pretty concerning, and they’d reach out to us about them. So, we add the note to give the transmission some time to adapt, just to reduce the possibility of having very firm or odd feeling WOT shifts the first time they try them out.
I've noticed the truck hasn't used 10th gear since the time upload, up through about a 70 mph cruise. Is that typical?
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First thing to verify regarding this is that your speedometer is calibrated accurately versus GPS. You can use a phone app like Waze to measure your GPS speed, and then you can calibrate your tire size using the on-device functions as described in the initial email. Transmission functions, as they relate to tire size and axle ratio, have a two-part logic. The first is making sure that the tire size and axle ratio are calibrated correctly in the calibration (tune) which we do when building your tune. That data is used to define the N/V ratio for the transmission. N/V is nothing more than the ratio of the engine RPM versus the output shaft RPM when the transmission is engaged in the 1:1 gear of the transmission. On a 10R80 that would be 7th gear. On other transmissions like the 6R80, there isn’t a true 1:1 gear. The closest to 1:1 is a 1:1.14 ratio, which is 4th gear, and the N/V ratio is calculated in a slightly different manner. The N/V ratio is a direct input into many parts of the transmission control logic, which is why it’s important to have the tire size and axle ratio data in the tune defined accurately. The next part of the logic is making sure that the speedometer is calibrated correctly. The vehicle speed is used more or less as a parity check to the transmission logic. Parity simply means that this value is used to determine if the vehicle speed being reported by the transmission logic is correct. While the system does not have the ability to disqualify the reported speed from the transmission control logic, if the speed reported does not match the speed being output to the speedometer, which in 2015 F150’s is controlled by the ABS module and is measured by the wheel-speed sensors, a discrepancy between the two can cause undesirable shift scheduling behavior. This is largely impart to several algorithmic based shift logic systems that exist in the control logic of these transmissions, and while those algorithmic systems are not defined or modifiable via tuning, they generally use things like reported vehicle speed, current gear, engine rpm, engine torque output, and what is commonly referred to throttle “aggression” which is a measurement of throttle rate percentage change over time (DOT measurement) and will use those variables to apply modifiers to the shift scheduling logic that allows the base shift schedule values to be modified slightly to provide or more intelligent and seamless driving experience as the vehicle encounters various driving conditions. So, it’s important that this system is being fed accurate data for it to work properly. Hence, making sure your speedometer is calibrated accurately is important. Adding onto this, the 10R80 transmission has three separate overdrive gears. 8th, 9th, and 10th are all over-driven. With ratios of 0.85:1, 0.68:1, and 0.63:1. In comparison the 6R80 had two OD gears; 5th and 6th, with ratios of 0.87:1 and 0.69:1. So, you can think of 10th gear in a 10R80 as a “super overdrive” gear. Meaning it’s really only necessary when you are at speeds where 9th gear does not provide ideal over-drive, and shifting to 10th gear would be more ideal. The stock calibration uses a “hurry-up and get to 10th gear” style of control logic. Mostly because that sort of logic might help with the very specific fuel consumption tests that manufacturers must complete for the fleet-side CAFE (Corporate Average Fuel Economy) standards that the manufacturers must meet and with trucks being the least fuel efficient vehicles that most manufacturers offer, they are often calibrated in manners that leave much to be desired in terms of driving enjoyment because they must often calibrate a vehicle to perform well for these very specific tests. Even if those tests are not very accurate representations of how the vehicle will be operated in real life. It’s an imperfect system and, often times, an unrealistic test. For example, having the truck in 10th gear at, let’s say 50 mph, while that might return a 1% improvement in fuel efficiency versus having the transmission in 9th gear instead, that 1% benefit in fuel efficiency would be completely offset as soon as you need to do something as simple as overtake a vehicle and your throttle input requires the transmission to kick-down 1,2, of maybe even 3 gears. The transient fueling that is injected during that throttle input and gear changes will be exponentially greater than the 1% improvement you were seeing having the engine in 10th gear versus 9th gear at 50 mph. So, knowing that, and also the fact that I found it incredibly annoying for the transmission to constantly need to drop down gears whenever I wanted to increase vehicle speed, only to immediately climb back up several gears ( I find that to make the transmission feel “busy” or “confused”, I designed a shift schedule that uses each of the 10 gears in the transmission in a more intelligent manner. So, if that means that 9th gear is a better gear for the specific speed you’re traveling and for the gear/tires combination on your truck, that is the gear that will be used. If you accelerate more, you will exceed the range where 9th gear is the ideal gear, and the transmission will select 10th gear.
Hopefully all of that makes sense, and we can definitely adjust your tune, but I wanted to make sure that you understood all of the logic that goes into the how and why I designed the tune and also that you understood how the adaptive logic works and that you are feeding it ample data for it to fully work and allow the transmission to adapt properly. Yes, it’s definitely possible for shifts to feel a little “off” as the transmission is adapting, but there’s no harm in that and you should not be overly critical or hyper-aware of the behavior. If you just drive the truck, barring you’ve done everything correctly in the installation instructions and calibrated your speedometer accurately, the transmission will settle in nicely. Shifts WILL be firmer than stock, as they should be. Firmer shifts are firmer due to reduced clutch slip time between shifts, and this is GOOD for transmission wear and longevity. Softer shifts are softer because the clutches are intentionally slipped, and this clutch slippage provides a smoother and almost imperceptible shift. For some people, they prefer that, and we can definitely set your shifts up like that, but it’s not ideal for transmission longevity especially when we’ve increased torque output of the engine. However, if you prefer this type of shifting, and you understand that there is a trade off with the softer shifts, I have no problem setting your tune up like that for you.
-Ken "Oz" Osborne
