I got into my 98 blazer this evening and tried to get it going to pick up my girlfriend from work. The truck was parked in a somewhat icy area. It was able to go in reverse a little, then when I shifted into drive it wouldnt move. I tried putting it into 4 hi, but it didnt want to go. I tried 4 low with the same result. I tried it again and it seemed to go in. Then the lights on the 4wheel switch all went out. When I pressed on the gas it acted like a car with a slipping clutch, badly slipping, except I have an automatic. The rpm would go up to 3000 just to get it up to 5mph. It was almost like it was stuck in 3rd gear. I have not tested anything yet, as it is dark outside. Any ideas where I should start tomorrow?

 

Did you happen to notice if the speedometer was working ? If it wasn't then it's the vehicle speed sensor .

 

The speedo was working. In drive I was able to get it up to about 10mph. In drive it doesn't shift. I can manually shift it between 1 2 or 3 via the shifter, but otherwise it doesn't shift.