Good Morning
I have a 02 dmax and am having a tranny issue.. just got back from a 2500km road trip and everything worked fine.. On sunday afternoon we took the boat out and had the truck deeper in the water than i have had before to launch the boat. after a day on the lake, drove truck home with no issues until the next morning.. no shift indicator and just throws hard into forward and reverse.. i was just reading the big sticky above about the switch and might have to try replacing that. also have the p0700 code.. is there anything else i should check besides the switch?

Thanks in advance to those who reply

Your NSBU switch got water inside. You can remove the connectors and try to dry it out, but most likely need to replace it. Look here or at an Allison distributor for a better price than at a GM dealer. Don't buy a gippo from an auto parts store. Its not worth the effort to put one of them on, won't last. Allison upgraded the switch from the original black GM one used on 4L_ Hydramatics.

We stock the Allison NSBU Switches.
http://www.merchant-automotive.com/allisonnsbuswitch2001-2004.aspx