Well took apart the diff tonight, first thing I noticed was the thing was literally bone dry!
no actual build up of oil, although thankfully the diff gears were 'moist'
Then I noticed that I only had one set of gears, whereas the guide on the Durango website shows two sets!
Heres a pic, just after I opened it. Slightly dark as from my phone:
Official shows it like this:
Anyone know if this is just an RTR thing? maybe older design. Any drawbacks? and how long should the oil remain the diff!! assuming Durango even filled it up properly in the factory!