Re: Shakes at 60mph...
If the vibration is still there coasting, I imagine the driveshaft is out of balance. It's an easier fix, but shop around, as prices will vary. I'd take it in for a proper diagnosis, as out of balance shafts are mostly found on high mileage vehicles, as the shaft will rust and pit over time causing a slow vibration that gets worse. Rarely, unless they decide to do some mild off-roading, will a lower mileage vehicle have an out of balance shaft.
Vehicles built from 1970's and newer shouldn't have any vibration when cruising at highway speeds, especially your 2002. Another thing to check are your tie rods for any play, along with wheel bearings. Wheel bearings can be a mixed bag, as some can cuase noise, some can cause vibrations, some can cause both, and some can cause squeaks and such when turning only. I've even had a wheel bearing that made a constant noise that got louder with speed, even when letting off the gas the noise was still there. With any luck it won't cost you too much out of pocket to diagnose and fix!
'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!