ok i have two (hopefully) simple questions and any help would be appreciated.

1. on my way to work this morning i noticed my wheel would shake back and forth noticably at about 25 mph. i stopped tightened my front lugnuts and checked the power steering fluid (which was a tad low, but my fluid in the trunk was frozen, so i didnt top off), and kicked off some snow from the wheels. the problem seemed to be solved, but i am wondering if there is anything else i should be concerned about (note: i have ruthlessly bombing my 25 year old rear wheel drive turbo 240 up my slightly snowy slightly inclinded driveway as nessacery according to the recent snow storm, and am a bit concerned it have have skewed something) any thoughts?

2. while bombing my car up the drive way i ahve noticed that when i get stuck my rear drivers side wheel doesnt spin (only one time, the most recent, have i noticed this), but the pasanger side does. is it possible that i have a rear axel problem or would that be more evident by my car always want to spin in left circle or something. it does veer a bit to the left but that could be any number of things. is this car equiped with a traction control system that would acctually stop that wheel from spinning if it thought it would be more beneficial i to spin just the right side wheel? any help would be appreciated.

thanks
steven