I had been sniffing around the notion of putting a locking differential in my P32. I tow a sailboat with it and launching ramps get very interesting. I had my interest renewed on a recent launching ramp joy ride. The Detroit Soft-Locker is what Tractec is recommending. I test drove a Dodge Ram Cummins diesel pickup with one (Man I wish I had that motor in my RV, strapped to a nice Allison). I really had no issues with it at all and they said the heavier the vehicle the less pronounced any side effects. It didn't bang or clang or click and getting suddenly on and off the throttle caused it to rock a bit but nothing freaky. I quickly learned the quirks of the pickup. This thing could claw its way up an oak tree.
The cost is very reasonable at under $600, plus installation. There's the rub. I'm now in the process trying to find an experienced installer in Ohio that will work on an RV. Setting up a differential is not an amateur event.
I suspect a P or W-series chassis with a Cummins diesel, Allison transmission and a Detroit Locker could quite easily tow my sailboat while chained to that oak tree.
I'll let you all know how it goes.