I have the same issue as Bennyp76 (hence finding this). What if I've just put in all brand new 'insides' with Home Depot toilet fix it kit? It worked fine but has just started doing the running sound with only a few seconds in between. Also, there's no 'arm' to bend.

terchap,
You piggy backed onto a 2 year old thread so I gave you your very own.
Which is your ballcock?(see image). Does the water in the tank spill over into the white overflow tube? Do you need help in adjusting the tank water level? Let me know. Tom