There’s a lot of debate about the Cummins 5.9 Killer Dowel Syndrome. There are definitely cases where the dowel between the engine and timing cover comes loose, falls into the engine and causes chaos.
However, DAF owners have not reported this happening, and inspection of the dowel shows it’s still firmly in place. The DAF engines were made under license in the UK, so whilst they are the same engine, the manufacturing process will be slightly different. The theory I have is this might be a US made engine problem…
With all that said, when you have the engine open, there’s really no harm in installing a retaining pin, so that’s what I did. Here’s hoping it doesn’t come loose, rotate 45-degrees and get shredded by the injector gear! I did put plenty of thread lock and torqued it up to be sure!