This winter our coach entry lock broke on our 2012 2551. It was a trimark model 060-0650. The plunger, made of white medal, cracked and the door handle became inoperable and unable to pull the plunger back to allow the door to open. My wife happened to be inside and I was outside. She let me in through the cab door and I was able to take it apart so that we could continue using it with just the dead bolt.
Upon returning home, I did some research and found this to be a common problem. Trimark does not sell parts and has actually discontinued this model and replaced it with Trimark model 060-1650.
Instead of putting more money into a Trimark lock I decided to upgrade with a Bauer EM Alsentis keyless entry lock. I read many forums and this lock got high reviews. It was not a plug and play replacement on the PC but installed very nicely after a few minor modifications. The Bauer company was very supportive in answering all my questions and even sent me an extra gasket to use for installation.
Comparing the two locks the Bauer feels very solid and closes very nice. The keyless entry is wonderful. The only cons I have read about them is that batteries may only last three months. However, you do get a considerable number of warning signs that the batteries are getting low. Since we keep the PC in our garage I will remove the batteries when in storage.
It also comes with a key override so I will always have a key handy incase the batteries fail on us. I picked up one of these
https://www.amazon.com/Master-Lock-5408D-Mini-Silver/dp/B0014EERFA/ref=sr_1_1?ie=UTF8&qid=1495398511&sr=8-1&keywords=mini+key+safe on clearance for $1 at one of our local discount shops. I keep it hidden on the outside with a key to the coach, a key to the cab and our toad key. It has saved us on a few occasions.
Barry