Been having twins since about November. Just rebuilt the NV5600....again. Twisted input, mainshaft 4th and 3rd teeth missing. Can't wait to do the Allison to say the least.
I think it might be a ground issue. I might add a 5V sender to my Insight and get rid of the gauge. The only drawback is I have to wait for the Insight to load up every time I start it up before I can see pressure, but it will be more accurate.
http://www.cumminsforum.com/forum/cummins-conversions-shop-talk-tools-fabrication/371248-2003-f-550-ford-cummins-6-0-torqshift-2005-ctd-nv5600-lots-pics.html