often time noise on deceleration is bearing related, especially with rear wheel drive vehicles with diff beairing going out, but we aren't dealing with a rear wheel drive vehicle. You say the noise wasn't present before you did the diff swap? What were you trying to accomplish in doing the diff swap? While you are in park a lot of things are still rotating in the transmission, none of them are the park paul or differential, so if you are hearing the noise in park, you can rule out your diff. Ten thousand origianal miles seems too soon for a bearing or torque converter to go bad, but anything is possible. Were you having trouble with the shaft that splines onto the park pawl and diff sun gear when you were reasembling? How far of a gap did you have between the diff cover and case before you tightened the bolts?
