My 98 expo's rear window now fails to latch/lock. I slammed it pretty hard, but it just won't latch up anymore. Is there any adjustment on the latch/lock mechanism?

 

try lubing the heck out of it with WD40. Rule out that the latch isnt stuck (like can happen to hoods)

 

Might seem silly but make sure the latch is open first.... Use the handle and if you hear it pop when you turn it, then there's your answer.... The other way is to use some grease.... See if a friend has a grease gun... Apply a LITTLE into the latch... WD40 is fine, but will last only so long