Icehouse
December 7th, 2012, 03:16 PM
I am in the middle of rebuilding my 74 K5, and have installed a 2004 8.1 with 4L85E. I would like to install dual transfer cases, but do not know how this will impact the transmission tune. The transmission does not have a speed sensor on the output drum. The output shaft of the second transfer case will have a 40 pulse speed sensor. I have not purchased EFI Live yet, but will do so when I get closer to firing the engine for the first time in the truck. This is the way I understand what the speed sensors on the transmission are used for based on my internet research. First speed sensor on trans is post torque converter, and second speed sensor is on the output of the transmission for 2wd or on the output of the transfer case for 4wd. The second speed sensor reading is compared to the first, and the computer verifies the transmission clutches are not slipping? The second speed sensor is also used for vehicle speed readings. Normally you have one transfer case ratio, and when you shift into low gear on the transfer case the computer is notified via a switch, and the transfer case ratio is programmed so that the computer still knows transmission output shaft speed? Also there is a new shift table for the transmission when the transfer case is in low?
So, what happens when you throw in additional transfer case ratios. Does the computer freak out? I know some have installed a speed sensor on the output of the transmission, and have never told the computer the tranfer case was in the lower gears. Is there a way to make it work with using the sensor on the output of the transfer case?
So, what happens when you throw in additional transfer case ratios. Does the computer freak out? I know some have installed a speed sensor on the output of the transmission, and have never told the computer the tranfer case was in the lower gears. Is there a way to make it work with using the sensor on the output of the transfer case?