How many miles a year do they drive??? In most OTR cases 180K should get you a years worth of warranty, not worth it IMO. And so far no one out there has taken the new trans over 100K that I have heard of yet so its still a new trans gamble. Parts for the new trans also may be more prone to backorder than the G56 thats in all trucks from 2500-3500C&C's.