No personal experience but my brother's brother in law buys them for his route managers. I believe they had 6 at last count. They've been bulletproof and get great fuel mileage. He gets rid of them @ 90k miles. He told me that was because the 3.0 uses a wet belt to drive the oil pump. The belt is at the rear of the engine so the transmission has to be pulled and the cab is also lifted to replace it.
Like this, not my pic just borrowed from the internet...
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I don't know what GM was thinking. It is a ridiculous amount of work for a maintenance item. I believe the service is usually around $4k at the dealer.
Maybe
@MechanicMatt could offer some thoughts as well.
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