I was driving for a vacation, about 3 1/2 to 4 hours in with the cruise set at about 62-63 my CEL came on. When i got back home from vacation had the code checked at the local advanced auto parts store, they say its P1870, i know this is cause by transmission component slippage, i have checked my fluid, its pretty clean, nice and redish pink colored. but it is a little over full, would that be an issue? o just had all 4 tires put on so thats not the problem. i have read about an aftermarket valve and sleeve that can be replaced in the valve body. does anyone know how long it takes, how much work is needed, and about how much it costs? I'm a diesel mechanic for International so i have mechanical background. also how big of a problem is this? should i not drive the car? i had the code erased and it doesn't want to come back on unless i go for a long drive. and 1-2 upshift is a little rough too.