My 06 LBZ has 235,000 miles on it. Would not hesitate to haul my trailer anywhere with it. Just did its first ever brake job. Did tie rods etc awhile back. Replaced a couple glow plugs. And the alternator. Extremely dependable. Injectors aren't normally an issue on the LBZ. And if there is an issue you only have to replace the bad one because they are on the outside of the valve covers instead of inside. Overall running around I average 18mpg with a heavy foot. I have no doubt I could average 20 or better normal hiway driving. 11 to 14 towing 9000lbs with a heavy foot.
Any Duramax check the upper radiator hose when cold. If hard could be head gasket issues. Whitch are very rare on the LBZ.
Towing my trailer down Jackson pass out of Jackson Wyoming I barely had to touch my brakes because of the engine and transmission combo. Also very easy to wire in the turbo brake.
Look on Silverado sierra duramax forum for tons of excellent info and lots of help. They have a dedicated LBZ section.
