Submerge the whole top cover in a container of Diesel fuel with some cheap automatic transmission fuel mixed with it and walk away for a few days. Fill the trans case about halfway with the same solution. Then walk away for about a week. That shifter and those gears didn't get stiff overnight, and it's not going to free up that way. Once the solvent works its way through the rust you should be able to get things moving properly. Get impatient, and you'll break some e$$$pensive bits and pieces!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!