Search and though Shall Find !
I did a How to on How to Lock a TT-01/TL-01 Diff.. Use Blu-tac or Chewing gum lol.
Cementing them is irreversible and not recommended..
http://www.rcuniverse.com/forum/m_4525622/tm.htm
Follow your Manual instructions for access to Your Rear Diff
Open it up, Cram Blu-Tac around the bevel gears inside the diff and reassemble