I have a pair of Lewmar 40 two speeds which I clean and lube every 5 years or so; they are from the mid-1980's. This summer I dropped a part overboard whilst cleaning and lubing on the boat.
. I ordered the exact replacement part from P2 marine:
Lewmar Winch Parts
Check the diagram on their website and make sure yours are put together properly. The palls should not fall out, but then again....