When my 2000 Durango hits 2000rpm it lurches forward and revs slightly higher then slips back down. This happens every 10 seconds or so -What causes this?

When my 2000 Durango hits 2000rpm it lurches forward and revs slightly higher then slips back down. This happens every 10 seconds or so -What causes this?
Sounds to me like you may be experiencing the wrath of that ever so popular, "lockup" converter. You can have a switch installed so that you can control exactly when that illustrious even transpires. I know. Hold back your excitement level, please. It will be tough to explain, but, basically, the torque converter, which kind of takes the place of the clutch on a stick shift vehicle, when stopping, or getting started out, is designed to slip a little bit. If the engine were connected direct to the trans, and differential, you would not be able to stop, and idle the engine, or, get started out without having the vehicle rolling first. Well, in a effert to save fuel, they made it so that it locks up, direct, anfter a certain speed. Bad idea. There has to be slippage there. Minimal, but, some. No big deal. It is doing what it is assigned to do. It is operating as designed. That doesn't make it right. Just functioning as designed...........chuck