Rear end Noise

[1993-Talon-TSI]

I got a 93 awd and the rear makes a graoning vibrating noise when downshifting and any time you let off the throttle while still in gear. The car has like 120,000KM (75,000MI)Any info or ideas would be great! Also i put in a new seal on the transfer case (The rear seal to the driveshaft) and the ting still put oil on the bottom of the car?? the rest of the transfer is dry just the out let to the driveshaft.
Thanks Guys

 

[sickandtwisted]

I got a 93 awd and the rear makes a graoning vibrating noise when downshifting and any time you let off the throttle while still in gear. The car has like 120,000KM (75,000MI)Any info or ideas would be great! Also i put in a new seal on the transfer case (The rear seal to the driveshaft) and the ting still put oil on the bottom of the car?? the rest of the transfer is dry just the out let to the driveshaft.
Thanks Guys

check the u joints on the driveshaft to see if any have play, and if you keep replacing transfer case seals the guide bushing might be wasted see if it wiggles in the transfer case. also check the pinion bearing see if the pinion flange wobbles up and down. if so your rear will need rebuilt