My TT was built in 2005 and I have used UltraLube (different brand, same as EZ Lube) since I got it (Al-Ko 5200 lb axles). I believe the system has finally failed after 9+ years as braking has diminished. There are other explanations possible and I will not know for sure until I take it apart. There are still no signs of any bearing issues (heat build up) or obvious grease leakage. Since I have done nothing other than add grease and adjust the brakes I would say my experience is an unqualified success and the system has worked exactly as designed. Others may have a different experience.