09 Charger 5.7L, PP, 149k miles. I bought it about 5k miles(1yr) ago. About a week ago, I noticed an odd occasional shimmy, which I first attributed to poor paving on the freeway. But the other day, on the same freeway, the shimmy became more of a shudder, bad enough that I caught the next off ramp, flipped a *****, and came right back to park it. It's hard to say, for sure, but it seems like it was worse when cold,, and worse when under load,, like mild acceleration or going up an incline. No obvious "check engine light" or other warnings. I have not put a scanner on it, yet.The tires are relatively new, brakes are great, auto trans fluid level appears about right and the fluid looks bright pink, like it had been changed in the recent past. Has anyone experienced a similar problem?