For warship, jumpship and dropship fleets the Clans are living off the 'capital' of the Star League. While they did make a few new dropships, jumpships and warships they did not even come close to building enough to completely replace what came with them let alone a significant portion of what the SLDF brought. For example, the Leviathans, Nightlords, new build Yorks, Fredasas and the retired ships from the Golden Century are a drop in the bucket compared to the McKenna, Texas, Black Lion, Aegis, etc from the SLDF in exile. And we know there were still ships in the caches (3 Kimi per the fluff) going into the 3060s. Jumpships? I do not recall reading anywhere the Clans were building any of the standard jumpships like the Monolith, Star Lord, Invader, Tramp, Merchant or Scout. They build some small ones like the Hunter, Odyssey,and Comitatus but only a few of these designs compared to how many they ended up with from the SLDF. Dropships is probably the closest they come to matching what they inherited- new build Overlord Cs, Union Cs, Sassanids, Carriers, Miraborgs, Mercers, Arcadias, Broadsword, and Outpost might match some of the numbers of what they inherited. But most of their transportation comes from the Star League- the Clans as a whole, even pre-Reaving do not have the support structure to build what they currently use.