did you remove the needles when you installed them, or was it the slip over kind?
i've seen on the site here people who removed the needles had to put them back on while the cars moving or something like that. might want to hit up the search to look for how they got them back on.
if it's the slip over kind you may just need to use a thin slice of double sided tape under the speedo in case it's bubbling up a little there and making it stick.
hope that helps some or at least gets you in the right direction, good luck!