Yesterday, My 2004 Dodge Ram SLT 5.9 C, 4x4, 6 Spd NV5600 Transmission finally broke down. I think its a clutch problem, because I cannot shift gears easily. But when I do shift into gear, my truck drives fine. I have over 251K miles and never replaced the transmission oil. I called my mechanic and he thinks its a "pilot bearing" problem. I should soon find out next week after they look into.