Thanks to all for your answers. Much appreciated.
I have googled this question -- about what the difference is between the 2006 LBZ (8th digit of VIN is D) and 2006 LLY (8th digit of VIN is 2, and 10th digit is 6, indicating the fact that it is a 2006). In the responses from you kind folks, I see there is a mix of opinions on whether the engine in the 2006 LLY is the same as the engine in the 2006 LBZ, except for the milder tune. I have also read that comparisons of engine part to engine part for these two engines have shown that all parts are identical, except for the tune. One place I read that the reason for the early 2006 milder tune was because the 6 spd manual trans was still offered, which was not rated for the increased horsepower of the LBZ tune. I don't know if this is accurate.
I don't know who is correct on this, other than that what I see online at diesel forums, when I google this question is that the predominant opinion seems to be that the guts of all 2006 Duramax engines are identical, except for the tune. Though there still are a lesser number of opinions that a so called 2006 LLY (going by the VIN #) is the same engine as the 2004-5 LLY.
The truck wasn't available to see today, so that is why we have an appointment to see it tomorrow. I am as yet undecided if we will buy it. Thanks again to all.
