My dually rather suddenly became extremely difficult if not impossible to shift from idle. I can put it in gear,then start it, it doesn't creep, but shifting going down the road up is ok,but to downshift takes a throttle blip to enable the shift. We are in Whitehorse Yukon with a 35' 5er wanting to continue our trip to Alaska actually tomorrow. Now I know that won't happen with this problem to deal with. The truck has 180,000 miles I purchased it with 110,000 5 years ago. As far as I know it's never had any clutch work done to it, and I did a lot of servicing and repairs that any 180,000 vehicle would need prior to departure and thought a lot about the clutch but it seemed fine sooooo I elected to try it. I'm suspecting the master or slave cylinder,and know haven't checked the fluid level, but will in the am. If it's low, it would have to have leaked right, I've not noticed any puddles and am usually very aware of such. I guess I'll shut up, and ask for HELP!, And Thanks for all Y'all do it makes the TDR the best thing since Grandma's pies.