Unusual Occurrence

Possible intermittent ignition switch. Had the same problem, 2000 Tropical. The switch does not always make full contact. When it doesn't and I try to drive away two things occur. 1) The transmission goes into some kind of limp mode and shifts extremely hard. 2) The speedometer also does not work. The first couple of times this happened the check engine light came on and would not reset by itself but it drove just fine once I restarted. Took it to Ford dealer after a couple of weeks when we returned home (we were in Wyoming at the time). They replaced the speed sensor and reset the check engine light. A couple of weeks later it happened again. It was then that I realized the ignition switch problem. Occasionally (every few starts) I noticed that the jacks had no power. I had to shut off and restart engine, then I would have power to the jacks. The reason I did not connect the dots right away was because when traveling and stopping for breaks, lunch etc I don't set the emergency brake or use the jacks. I just start the engine and drive away and occasionally would have the problem. Now every time every time I stop I set the emergency brake and before I take off again I start the rig and verify good contact by turning jacks on and off (emergency brake needs to be on). I don't actually have to put jacks down, I just need to make sure the jack light comes on. About every four or five starts it doesn't make good contact and I have to turn engine off and restart. I believe if I changed ignition the switch the problem would go away. However it doesn't seem worth the trouble since I have had no other problems because of the switch and I have been using this procedure over three years.
It has been several years since I wrote the above and what I wrote is still true today. I religiously go through procedure every time I start.