I have a 2001 pontiac grand prix with 121k miles, today I got a P1811 code, time to time I get hard shifts for 1-2. I drive 10 miles a day for my teaching job. I checked the selonids using the scanner, it is working through the gears as it should be. I changed my transmission fluid with valvoline dexron 3, 3000 miles ago with new filter, the fluid level is OK, and color is good. Is it true that when you change your fluid, it is common to have hard shifts and does it go away once the fluid gets older say after 10k or 20k miles? Is it okay to drive the car for another 1000 miles? What are my options? Put new selonids or full transmission rebuild? The car may worth $500 but it is worth a lot more to me, I have this car for the past 13 years. I drive 2000 miles a year. Any suggestions or opinions are welcome.