I need HELP!! I have a 1989 ford ranger v6 4x4 and I have a real hard shake when i start driving. I put it in gear and take off and i get a hard rattle that feels like it starts right below the shifter for the 4x4 and works its way back till it finally goes away. It only happens from about 5 to 10 mph then it is gone and does not come back until i make a complete stop and then start going again. The transmission is newly rebuilt with only about 1000 mile on it and i have had all the u joints from the transfer case to the rear diferential replaced and have also replaced the center support bearing. I can put it in neutral and rev it up and not feel it, it is not until i put it into drive and start going when i feel it. CAN SOMEONE PLAES HELP!!!