Originally Posted by echo
Those 6.5's are a crap shoot. Every so often they built a good one but for the most part the majority are/were lousy. They couldn't compete with Ford or Dodge and had to come up with the Duramax.
Could be wrong but I thought its a 3speed and why you'd see them crawling down the highway.
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The 6.5 was not a bad design and have served the military well. The problem lay within GM in their poor attempt at adapting the engine to the trucks. The way GM had the cooling systems designed caused many of the engines to run too hot and crack heads. The engine has always had lackluster power compared to other newer diesels from Cummins, Isuzu, and International. The 6.5 is a true diesel design and could have easily been de-bugged by GM but it really was just meant to fill the gap GM had in their light truck segment until the newer Dmax design was ready. GM owns a small percentage of Isuzu and it's a good thing they do. Isuzu's diesel is a key player in modern diesel design. Their gas engines leave much to be desired but their diesels are known for long service life. I run older trucks and keep them well maintained. They spend little time in the shop mainly because I am the main one behind the wheel of them so they get treated well. Everyone has priorities and for my situation spending 50 grand on a work truck isn't how I choose to spend my money. I'd rather buy a piece of equipment for my farm or update my property. To each his own.