Just got back from the Caribbean and came back to my truck sitting in the airport parking lot, for a week, after it endured the bad snow storm and cold temps. Plowed through the snow easy enough but noticed a shimmy around 65 mph. This lasted for quite a while (all the way home). Finally got home but every time I got 65 or higher, it was there. This sound like anything?

 

probably got mud or something on your driveshaft.. or it was on the shaft, but melted and migrated t oone side....

 

Snow and ice packed inside one or both of your front wheels.

or

Some tires get a slight 'flat spot' after sitting in one position for too long. An extended drive tends to take care of it.

Andreas