Driving last night on the highway after about 40 miles, the trailer blazer I owned for the past 2 years, (which I have no major problems with now has 217K miles) made a strange (gear whining) sound while driving about 70 MPH. Then it seemed like a bouncing issue in the right rear tire area. I rest stop was coming up, I pulled in thinking it might be a tire issue. Got out checked the tires everything looked fine. I left the engine running, when back in the truck the 4H was on the 4L was flashing even though it was in 2 wheel drive. For some reason I turned the switch to 4L back to 2 the lights went out and drove home with no problems. Any one have this happen?