my rear chevy door wont stay shut

i have a chevy 98 and the rear door wont stay shut no matter how i bang it. but all sliding doors work fine. can anyone of you good guys help me please

First of all, make sure it is unlatched and you aren't trying to shut it on a closed latch. Second, make sure the locking mechanism isn't gummed up and that it is properly lubricated with some white lithium grease. Assuming that is not the problem, you may need to simply adjust the striker, which is the piece of hardware on the floor on which the rear hatch lock catches. If the striker bolts are loose, that is your problem -- simply reposition them and tighten. If the striker bolts are not loose, try loosening them, moving the striker back (toward the rear) a little bit and retightening the bolts. (It's a really simple mechanism and it's harder to describe what I'm telling you than it is to actually look at it and do it.) Good luck and let us know how it turns out.

I would definitely check to see if the rear handle is releasing like AJT1961 says. If you live in an area that uses salt on the roads in the winter, then this seems to be a problem, ( it sure is in Upstate NY as evidenced by the people I talk to.) My '97 has been doing it for many years now as well as my '94 Chevy C1500 pickup (rear handle on tailgate.)The handle seems to stick in the "open hatch" mode, and won't release back to it's original position. I go through the ritual every year of blasting a spray cleaner(WD40 or PB Blaster works well) on the mechanisms then spraying lithium grease on it. After the "treatment" the door opens and stays shut much better.