There's a few possible causes for this, but having so little information, I can't really tell you much.
If there's a lot of miles on your tranny, then this will happen eventually anyway. Also, how old is your fluid/filter? If it's really old, try changing it.
Also, solenoids can go bad sometimes, depending on the age.
Sorry, but if you can give me more details, maybe I can help or provide you some more suggestions.
SPONSORED LINKS
Thursday, November 18th, 2010 AT 4:50 PM