Any idea how the timing cover housing would break and how big of a job to fix or how much tks

 

Do a search on KDP.

Its a biggie, front of engine off.

 

KDP (Killer Dowel Pin)= the upper timing cover locator dowel pin

Here's what it takes http://www.cumminsdatabase.com/read.php?id=111

If you do the work yourself and only the cover is broken it's about $400 for parts.
It's a lot of labor, last I heard it's about $1800 at the dealer.

Of course it all depends on if there is other damage besides just the cover.
Worst case scenario is a new engine.

 

On the other hand. If engine is running fine and timing gears are not making noise.Listen to this
It has been rumored from some faraway place that a inexpensive repair has been successful. It is said that finding a hole in cover housing with no cracking. Clean the hole carefully and patch with RTV. It can be reinforced with some plastic screen wire if over 1/2 inch. It is difficult to get to but not impossible in most instances. Many times the dowel can be found in oil pan at next oil change with magnet on wire in drain hole. Take it for what it's worth, since the JuJu indians in South American Andes mountains if where info came from.

 

I think the dealership charged like $2100 when the KDP dropped on a truck at work...