My first thought would be something going out in the 3rd member like the spider gears or something. Do you have a rear locker? (If so, which type) Next thought would be the center support bushing (aka carrier bearing) for the driveshaft.00Andy said:Last weekend I replaced the stock (burned out) clutch in my 2.7L with a Marlin clutch. I love the Marlin clutch but whenever I let the clutch out too fast in first or turn corners while accellerating hard in 1st, I hear a grinding/clunking noise from the rear of the pickup. I've tightened everthing back up to factory torque specs and I can't see anything irregular (and believe me - replacing a clutch makes you very familiar with your truck's undercarriage). Any ideas as to what this could be? So far it hasn't caused any problems but it is most definitely not a good noise!