Start with a clean filter-- might have water in the fuel.
The 700 is a code that senses a trans problem-- that turns on the check engine light-- there is always another code-- ???
You might have a transfer case problem- see if the transfer case has fluid, and also it there is excessive slop on the output shaft of the TC.
Chevy 04.5 LLY, 2X, shell, XDR, MikeL Heavy duty up-grade, 6spd, TransGo, deep pan, de-badged, 65 Gallon replacement Aero tank, LBZ-mp, Kennedy pump, shimmed, Pre-fuel filter, tow mirrors, BU cam, gauges, GPS, Sirius, bags, custom grille, fender vents, HD trans cooler- Curt front hitch, footwell lights, load lights, Studs, head gaskets.--- Jerry