Illya, you have a PM with all the info you need.

Its not a bad job to do, pull the driveshafts out, pull the transfer case out, remove the extension housing, remove the intermediate shaft, pop off the large snap ring, pull the governor support off. The rings are actually located on the overdrive drum which is bolted into the case. Use crocus cloth to polish the valves and governor housing. All the governor parts must be completely free with ZERO binding. The process is time consuming but not overly difficult, just make sure everything goes back correctly. The rings must not be rolled when installed, but put in so they maintain their natural orientation. You will understand this when you get the parts in.