I have just put some H2 takeoff's on my 06 and have noticed that all of the shift points are at a higher speed then before. I have done a search and found that the Alli gets it shift point information off of the output shaft RPM's, but some say that it will learn to shift earlier over time, and some say that it will not?

The speedo has been corrected, it matches a GPS perfectly through 5-105 mph. I do not know whee all of the shift points are taking place currently, but I do know that it will not go into 5th lockup until 54 mph where it was at 46 mph, and it will lock up in sixth at 62 mph where it used to lock at 54 mph. Like I said, I did do a search, several actually so if this has been beaten to death already then I apollogise.

Oh, about 300 miles on it so far but 170 or so have been on the highway. And my fuel mileage has taken a very serious dive. :eek:

I always thought they worked off engine rpm.

The speed sensor input is used by the TCM and larger tires will not be considered by the TCM. You didn't say how the speedometer was corrected or the difference in diameter of the tires so it is hard to guess the outcome of your swap. I had 265/85r16 in my truck for awhile and it never did shift as firm as the original 215/85r16 originals. My speed sensor input was used to correct the speedometer and that did help but since I removed the bigger tires I'm happier. Your mileage should not have changed that much,(mine didn't).

If he went from 245's to 315's his mileage sure as heck would tank.

The TCM keys off of rpm (as well as other inputs) so with the larger tires (and the adjusted speedo), that would equate to a higher speed at shift (but same rpm).

DEWFPO

If he went from 245's to 315's his mileage sure as heck would tank.

The TCM keys off of rpm (as well as other inputs) so with the larger tires (and the adjusted speedo), that would equate to a higher speed at shift (but same rpm).

DEWFPO

He has not yet said how the speedometer was corrected. If he used one of the aftermarket device to alter the speed sensor output it would also be seen by the TCM so in effect the larger tires would have given him a lower rearend ratio(traveled further with each rpm of the engine) and this would probably helped mileage in an unloaded truck.

I used a programmer to set the speedo. I can live with the different shift points, but if the mileage totally tanks then I will sell the 315's and go to a smaller diameter tire. I will say however that the air pressures were set too low (never trust a seller for the right information) so I am hoping that inflating to 50 lbs will help. I know that the MPG will suffer, but I will not accept a 3 mpg drop.

You'd need something like EFILive to change the shift points. On my 2003 with the H2s, the shift points are different..IE the Torque converter wouldnt lock up until about 60.

I used a Predator to adjust for the tire size/speedo correction on my truck when I went to H2's w/ 315's. My truck locks the TC in 5th at 54-55mph at around 1500 rpm. As previously mentioned it used to lock up in the mid to upper 40mph range but that would be due to the rpm's (which were the same). I can't really comment on the mileage due to only driving very short distances lately with lots of stop and go (11-14 mpg). Come December and January I have some 200-1400 mile trips planned that will give me a more accurate picture of mileage w/ bigger tires. If the 315's suck, I'll probably drop down to some 285's. My .02

wot shift are rpm 3200, 3300.......

part throttle shifts are MPH......

wot shift are rpm 3200, 3300.......

part throttle shifts are MPH......

I agree with this, but since the speed sensor is on the rearend it doesn't know your tire size and the signal used sent to the TCM will be incorrect, hense the different shift points with larger tires.

I agree with this, but since the speed sensor is on the rearend it doesn't know your tire size and the signal used sent to the TCM will be incorrect, hense the different shift points with larger tires.
correctinghte speedo will change the part throttle shift points

I used a Flashpaq to change tire size for speedo and it is accurate now with GPS. I can adjust shift points with the Flashpaq. Do I need to increase or decrease for better mileage? I am now running 285/75/16 Nitto terra grapplers.

I used a Flashpaq to change tire size for speedo and it is accurate now with GPS. I can adjust shift points with the Flashpaq. Do I need to increase or decrease for better mileage? I am now running 285/75/16 Nitto terra grapplers.

If you shift sooner you see a slight increase in mileage but it will be hard to measure it as the variables of refilling the tank will cause more of a difference. You can go to extremes and changte to soon and lug the engine which will cause more useage, I would stay with the factory settings.

i put the accu pro calibrator on my truck when i had 35 inch tires put on with the six inch lift. i have actually gained some fuel mileage and still have stock gearing. my rpms are a little less and my shifts are decent. i actually am now going faster speeds at lower rpms.