truck wont shift into overdrive
 

hey guys i just got done with my 2wd to 4wd swap and everything is good but it wont shift into overdrive. then overdrive unit i bought is used. everything worked perfect before. one thing im kind of second guessing on is the overdrive clutch, there is a spacer and i think i remember it sitting on the clutch but im not 100% sure! im at a loss of what to try now when i press the o/d button then nothing happends

completely tear down that OD unit, and go through the clutches one by one.... ALWAYS check your fluid levels in hot and neutral... Once those valves open up, that tranny gets THIRSTY