Wow. The rpms do drop in last gear. I most definitely would consider this mod. Is there any concern with offroading and the converter lockup?
To answer this, there was no issue in low range, I was monitoring it on the laptop and it went into lockup in second gear and stayed there as long as I was feeding it fuel but I have noticed that in gears between 2nd and 4th the TC will go out of lock most of the time when the accelerator is at 0%, then as I add fuel it will within a few seconds will lock the converter again.
Rock crawling would really benefit from manual shifting, one of my many upcoming projects.
The 4.030:1 VS 2.480:1 (4L80) 1st gear is awesomely slow.