Actually, I have a few good examples of an /l/ versus /l=/ distinction before diphthongs, and how it is often "silent" in default forms and only shows up in inflected or derived forms:
"owl" : /aUl/ -> [aU.5=]
"towel" : /"taUl=/ -> ["t_haU.5=]
"owling" : /"aUlIN/ -> ["aU.5I~N]
"towelling" : /"taUl=IN/ -> ["t_haU.5=.I~N]
"roil" : /roIl/ -> ["r\oI.5=]
"royal" : /"roIl=/ -> ["r\oI.5=]
"roiling" : /"roIlIN/ -> ["r\oI.5I~N]
"royally" : /"roIl=i/ -> ["r\oI.5=.i]
"owl" : /aUl/ -> [aU.5=]
"towel" : /"taUl=/ -> ["t_haU.5=]
"owling" : /"aUlIN/ -> ["aU.5I~N]
"towelling" : /"taUl=IN/ -> ["t_haU.5=.I~N]
"roil" : /roIl/ -> ["r\oI.5=]
"royal" : /"roIl=/ -> ["r\oI.5=]
"roiling" : /"roIlIN/ -> ["r\oI.5I~N]
"royally" : /"roIl=i/ -> ["r\oI.5=.i]