from the evidence so far im surprised the dealership isnt offering to rebuild the engine and fix all for free as the cause of the engine failure is looking 100% cats fault, if this went to court and the 3 ring circus of a dealer is presented to a jury they would award all kinds of good things to the original OP including down time of dozer and OP aggravation expenses( all the time spent on trying to get his dozer fixed) , alot more cost to the dealer than just getting it fixed...I hope you go for the jugular on the dealer, anything less they dont deserve....