[njsteve]

Probably! But after they accurately predicted the diesel engine in my Suburban was in the process of a catastrophic bearing failure, and the Viper's pinion bearing failure, I am definitely a believer.

It was 4 years and 10,000 miles after I had replaced the head gaskets after one blew towing my SD455 out to MCACN. Engine running fine, no noises, no symptoms. Just as ongoing maintenance I sent the sample and got the results back saying that way too much lead, tin, and copper were in the oil. That gave me time to order a brand new 6.5 diesel engine from the Humvee refit facility in Ohio, have it delivered and then installed it myself in the driveway in July of 2017. We then went on our planned vacation trip in the Suburban and it performed flawlessly up to Maine and back. When we got back I autopsied the original engine and all the bearings were flaking from the antifreeze contaminated oil that occurred during the original head gasket incident. And an added bonus was finding that all the main webs were cracked (a common 6.5 malady). Can you imagine having a diesel failure during a cross country family vacation? Just getting it towed back home would have been half the cost of the new engine, not to mention the entire lost vacation cost!

And just earlier this year the diff oil sample from my Viper said I had 50 times more iron in the oil than should be there. Impossible, I said! Until I pulled it and had the machine shop inspect the unit. Turned out the pinion bearing was in the process of devouring itself. Here's the comparison of the rollers. Notice the "slight" size difference between them? The only symptom was a strange "tinkling" sound when I drained the fluid and rotated the gears. Turns out that was the sound of each roller falling to the opposite side of the bearing cage as it rotated.

Here's the 6.5 bearings, cracked block and the Viper pinion bearing: