speedo troubles

[73chgrSE]

My speedo works ok on the way up to 55mph but right after it goes nuts like its an upside down pendulum.  Will I need to replace the whole gauge or a component. How hard is this to do yourself. 73SE

[Nacho-RT74]

check first for speedo wire. Probably loosen on back of cluster

[NHCharger]

Do you hear a humming noise from under the dash when this happens?
Check out this thread.
http://www.dodgecharger.com/forum/index.php/topic,11279.0.html