when I put it in drive or reverse it gives a little jerk.

Hello, hard to say if the "jerking" you are experiencing is normal or not. When you feel abnormal jerking when shifting from park to drive or reverse, I typically would inspect engine and transmission mounts for possible torn rubber or separation, causing the drivetrain to move more than normal when shifting to reverse or drive. If you need some assistance with this, click this link for some shops near you that can help! http://repairpal.com/lexus-within-10-miles-of-new-york-new-york-10109