The GM 6.0 has been good since it's introduction, not many issues known. If you get the 4 speed version try to get the 4:10 gear set. If newer and 6 speeds then 3:73 is fine. I pull in 5th OD in Florida, and when I hit a hill it will lose some speed but stay in gear in florida. When outside florida and larger hills I will drop it to 4 th gear, run 3100rpm and keep 65 mph easy. Overall the only issues I have had were broken exhaust studs, water pump at 150k and CPK sensor on my 02. Had the tranny rebuilt in the 02 but only because the TQ converter went south. Overall the 6.0 with the 4l 80e(4 speed) or the newer 6.0 and 6 speed in late 07 and up are excellent trucks. They are proven workhorses and will last. I have had both diesel and gas, so it's really up to what u like. For me, well I only tow 5 times are year or so.. Because of this and the simplicity of gas I chose to stick with a gas truck. I can work on my own truck which is important because I really can't afford to always pay another to do so. With that being said, the 6.0 is one of the easier engines in my opinion to work on. Chevy gives you plenty of room engine bay wise to get the job done. Despite what you may be told, it's cheaper to work on a gas engine. Parts are not all that expensive either. When we had the 02 duramax... Man that thing was a tow beast but when the head gasket went and 2 injectors said goodby... Well got traded in.... If not then about 4-5 g would have fixed it.... I could buy a brand new crate gm 6.0 for less then that...but if u look at diesel then the older cummins, or ford 7.3 is good. The duramax is still my favorite overall when it comes to diesel. The problem is that the older diesels usually have high miles.... Then you hear....well she will go 500k, however everything this else on the truck goes south and it's just one big money pit from then on. If your friend had the 06 and u know the truck well and u trust him, then that may be the way to go in my opinion. Good low miles and good service should give you many years of great service.
