Since it's a 2008 Puma it would have been out of warranty for a few years now.
Have a look at the Harrop e Locker. Much neater than air lockers as there's no compressor to worry about. Quieter too. Each locker draws 4 amps when in use. I've had some experience with an eLocker and have been happy with it. I've never been a fan of air lockers - too many stories about oil blow back from the breather tubes, plus there's more components that can potentially fail.

