I have an 02 6.0L vortec out of a Yukon Denali (DBW) and a 4x4 4L80E, NP 241 transfer case behind it. The transmission is currently tuned for 2WD so it works great in 2 hi and 4WD hi, but the second 4 low is engaged it wont shift out of 1st unless manually shifted. The VSS is located in the transfer case. Since the gear ratios are different in 4low a 2WD tune isn't going to do me any good if I want full use of the transfer case. In the 4WD trucks of this year, the PCM looks for a ground signal on pin 16 in the red connector when 4WD low is engaged to shift properly. I will be running a switch on the manual shifter for the transfer case but I need a 4WD tune for my 4L80E. Anyone that is familiar with this issue have this file?