My first XC90 and am having issues

Hey guys, this is my first XC90. It's an '05 with the V-8, has 196K miles. I believe I am having some transmission issues. The car goes real smooth on the up shift when picking up speed. As soon as I back off on the throttle, it shakes like the motor is falling out. When I'm coasting down on speed, you can feel the jerk when it down shifts. On one of those shakes, it did something to the rear main. It's leaking oil, leaving about a 12" spot in an hour. What I'm asking is this a common problem or is there something else going on? Any input?
Have you taken it in. With engine shudders, the first thing I check is the motor mounts, if the rubber motor mount has failed vibration is not isolated and dampened and can cause these issues

[MENTION=1087]Bmoe99[/MENTION] , I haven't taken it to the dealership. Closest dealership is 180 miles away. Did find a guy here that doesn't mind working on Volvo's. The motor mounts and transmission mounts have been replaced as well as the top cross bar mounts. Still has the problem. If I keep under 35 mph, you can feel the jerk when it downshifts, over that, it shakes hard. The faster I go, the worst it gets. I talked to the Volvo tech and he says transmission. I'm not sure if it could be the torque converter not releasing or what. The oil leak I saw is from the power steering pump. Got that fixed. Right now I'm keeping a lookout for a used transmission and will try that.