Cars shakes so bad when put it gear looks like it's gonna jump put

Could very well be a engine mount. Any misfires? You can check mounts by putting on parking brake, putting into forward or reverse gear and "power braking" the engine. Look for major movement from engine in either direction

The engine mounts and transmission mounts are essential for limiting engine vibration. When an engine shakes badly I check the mounts first , unless another cause is obvious. Do the test recommended above and if necessary replace engine and transmission mounts all at the same time.