Whenever I give the car gas the full power is not making it to the wheels. For example I could floor it and the the motor would go at full power but the car would barely get moving. I have taken apart the center diff and refilled it multiple times. I think this is starting to lead me into the front and rear diffs but I haven't dove into that because it's honestly a little intimidating looking to try an get to the center diff and I honestly don't know where to start disassembling. Any ideas on what this problem is and or how I could solve it?