Hello, I have a 2005 4 wheel drive small 8 automatic Durango, I changed the trans fluid and the filter, but sometimes not all the time, it doesn't want too go up the hill in drive, it goes into reverse just fine, then the next time it will go up the hill with no problem, can anyone tell me what the problem is, do I need a new trans or what?

 

Probably need to take it to a shop for a proper diagnosis.