I took my 08 F150 to the dealership cause It feels like the tranny is slipping. When I hit about 20-25 the RPM's will jump up and the truck doesnt go any faster, then it jerks into gear. When I took it to the dealership they claim its the computer decideing on what gear for it to go into. Is this true, because i doesnt rly sound like it is. So what should I do about it?