Transfer case "pump rub" is an issue that can show up between 70k and 120k. If you catch it in time it isn't too hard a job to do the upgrade ($150 in parts and 4 hrs labor).2002 Duramax 2500HD 4door 4wd. pros and cons for this year truck? (i know nothing about them and have no brand loyalty to any flavor) Listed at $9K private sale.
I'm not as up on duramax's but I believe 02 - 04 is the LB7 engine and the LLY started in 05. The LB7 did have some issues but at this point if the truck is in good shape I wouldn't worry about it any more than the other things that can go wrong on a truck in that age range, the injectors can be replaced much more reasonably at a local shop instead of a dealer. Some LLY's had an overheating issue that I'm not sure if it was ever solved. The duramax's in general are very good engines.
LB7 (engine code "1") was first introduced in 2001 and continued until mid-2004....
The LLY (internally called the 8GF1) (engine code "2") is a 6,599 cc (402.7 cu in) turbocharged engine which debuted in mid-2004 and continued until the end of 2005
The LBZ (engine code "D") debuted in late 2006 and continued into 2007 sold only in the "classic" body style.