Lincoln/Mercury Repair: 95 Cougar Odometer, head assembly, steady hand

Question
I have an analog cluster.  Everything besides the Odo works.  I have located some replacement gears on-line.  Is removing the cluster and replacing the gears especially tricky and/or difficult?  Or is it just a screwdriver and a steady hand?  The dash and cluster look great, and while I am "ok" mechanically, I'd hate to louse up the cluster either.  Thanks.  Car is automatic with the 4.6 by the way.....

Answer
Very tricky Steve. If it where easy, everyone's car would have less then 10,000 miles. They normally sell the entire speedometer head assembly as one. The information I have does not show how to replace just the gears and states that the speedo head is non serviceable.