All lights on my 4wd selector switch stay on. Last week I heard a bunch of clicking coming from the passenger side lower dash area. Since then the clicking has stopped. All the lights remain on and don't appear to do anything when I hit them. However I got in the truck this morning and when I took of as I went from first to second gear it felt like I was going over a rumble strip and the tach dropped down to 1000 rpm. I gave it some more gas and it accelerated normally above that gear. Any ideas. Fluid level is good and Trans fluid is clean and smells as it should.