Rear Shudders

I drive a 02 Wrangler sport, inline 6, manual, 4 wheel high and low, with 37,000 and everything is stock. Just recently the rear end began to shudder at speeds between 60-70 and only when I accelerate. The wheel shakes just a little bit when this occurs. However I dont think its an alignment issue because when I let go of the wheel she stays straight. The tires are down pretty low under 1/8 inch. Another problem I have with the jeep is there is a very small oil leak where the transmission starts right past the oil pan. It only leaks for 5 minutes after I turn it off, and only drips 5-10 drops. The oil gauge stays between 40-60 however I notice it likes to stay more towards the 60 side. I checked the oil and it is in the right limits. Someone told me the shuddering could be a bearing going out but any help you guys had would be appreciated.