Company truck, 07 C3500, 6.6L Duramax, Allison 6 speed trans. 116K 3 weeks ago replaced original battery. truck started right up, no warning lights, ran fine. sat for about 2 weeks with out being run. (previously had sat for months at a time and never had a problem starting) went to start after 2 week period, had dash lights but no turn over. put battery on charger, charged until charger turned off. started it up. check engine, ABS, and brake lites on. took for a short drive, noticed no speedo, no lite on gear indicator, seemed like it was in second and would not shift, and had reduced power. stopped to turn around, shifted into R, seemed like i had thrown it into gear while moving, same when i went to Drive, even though i was completely stopped. got it back to garage, shut it off. went to start again, battery lite and all others as b4 on, would not turn over. will a weak/bad battery cause all these problems to happen? and will a new battery eliminate the problems? will be pulling battery to have it checked tomorrow. it's not the first time i have had a battery go bad in a month.