Riding With the KING! Going to see Rawze!

[Chamberpains]

You said the warranty was out on your engine by a couple days. If they used genuine Cummins parts, can you get the shop that did your rebuild to maybe sneak the failed parts in under Cummins Parts warranty? Maybe they'll make a report or work order up that shows the failure occurred before the warranty was up. Some shops are willing to do this to help a guy out. If they used genuine Cummins every part they had has a serial number and should be recorded. I know mine has a two year Parts warranty and can be pulled apart and sent in for coverage by using the purchase receipt as date of installation.
You'll be out the labor you're putting in it and time down. But maybe you can mitigate some of your costs by having Parts covered. I would think it was only decent of the shop that charged you $38k to help you out a little bit. And it won't cost them more than just making up a work order to show time of failure within warranty.