I am looking at acquiring a 2001 Chevy 2500 HD 4X4. The truck has 63 000 km (about 40 000 miles) and the asking price is $31 000 Canadian (about $20 000 U.S.) The body is in excellent shape and it was never used for heavy work or plowing. What concerns me about the truck is the engine. When I took it out for a test drive, I noticed two things: 1. On start up, there was tick, tick sound for 15 seconds or so. 2. The truck was very sluggish on the road, seemed to be hunting for gears and was struggling to get up small hills. Is this normal for this engine or does this engine have that dreaded piston slap condition that a lot of the GM trucks from 99-02 have? Can anyone help me out with this?