6.1 (2010) lifters to replace ( ticking noise )

My 5.7 has ticked since new... I asked about it but they said it was normal. Sounds like a header leak or 1 loud injector. I have 138k on it now.
exactly. But at cold start its quite. With warming up it gets louder. Read yesterday about in deed about pushrod issues in the upper Cup area. changing them is way more inexpensive than changing lifters. I do flush the engine with ATF as someone said and fill thicker oil like Mobi1 10w50 or Motul 300v competion 15w50 thanks for that advise, have never thought about the viscosity.
if this is not giving the solution i change the lifter. from cheap to expensive... :)