I need to take my truck in for some warranty work. Can anybody recommend a dealership in northern IL that has worked on the duramax. My truck has a shudder type shake right at 1600 rpm before shifting from 1st to 2nd and is really bad when under a load. No codes have been thrown. So I want to take it to a reputable dealership thats not going to waist my time with the guessing game. I am in Kingston. 10 miles south of Belvidere and 15 north of Dekalb. The Allan Browne Dealership is 3 miles from me but i dont know how much experience they have with the duramax.