Hello. I have a 4 stop dual above ground 3 stage telescopic Tac 20. It is racking along with an occasional loud bang As it gets close to top floor. I can manually sync up the jacks and it will run smooth for maybe a day or so. The car syncs up everyday at midnight also. No fault codes and no air in lines. Oil is clear . There are no signs of oil leaking from seals. Is this possibly the inside seals and synchronized valves causing the problem ?