I have a 02 ssei been having a random issue with my transmisson the problem is when i shift into drive it seems not to go into gear. And will lag really bad 1,2,3 work fine when this problem occurs it has only happened twice in the past week check fluid it is full and has a good red color i was thinking maybe a sensor was going bad because once i shut the car off and start it again it will go away any ideas on what can cause this problem

Dex6 works best in our engines so if your not using that u shlould be because these trans get very hot and anything less than dex6 might give u the problems your having.....