This has happened twice. The gear indicator on the dash goes dark, and the tranny shifts very harsh. Turn the truck of for 10-15 seconds and all is well again, last time was about 4-6 months ago.

I cannot for the life of me recall where I saw a thread on this, but it sounds like the range sensor on the transmission. This will tell the tranny what position your shift lever is in. Tell-tale signs of this are the erratic behaviour on the gear indicator in the instrument cluster. Not sure why it happens so sporadically, maybe a random short in the wiring. Sorry I can't be of any more help..... perhaps someone here will be able to direct you to some more info. It could be something else but maybe this is a good starting point.

I cannot for the life of me recall where I saw a thread on this, but it sounds like the range sensor on the transmission....
That's exactly what this problem is. The dielectric grease in the sensor dries up / melts away, or you get moisture / dirt in it. Do a search for "range sensor" or "mode sensor" and you find info.
G/luck
Joel

http://forums.vmag.com/suvrodeo0300/messages/1939.html

This has a bit more information on the problem, courtesy of Google.

I also have this problem, exactly as described. Rough shifting intermittantly, and a mismatch between the lights on the dash indicator and the actual position of the shift lever.

I'll share any insight I have when I try to fix it this evening.

Where exactly is this sensor located? I'd like to try cleaning, relubing before I deal with the local dealer.

Dave- it's a credit card sized black box attached to the shift arm, sticking out the right side (drivers side) of the tranny. It's got a fairly large electrical harness/plug, plugged into the top of it. IIRC- there's two small bolts that hold it in place & one nut attaching it to the shift arm of the transmission. Unplug it, take off the two attachment bolts, the nut, and it comes right off. The newer ones have a metal heat sheild that clips to the side of it, pull that off first if yours has it.
G/luck
Joel

Thanks Joel, I assume that you can disassemble it somehow to lube/fix it. I did find out that it will have this problem if I drop the shifter into low, so I know what to do to test it when I'm done.