Nitro Hobao Hyper ST - CENTRE DIFF REPLACMENT

Following on with the Hyper ST series, we saw this car go from a rusty wreck to a gleaming and running RC Truggy. However if you remember the previous video I noticed an issue, where the engine RPMs were not proportional to the speed and thought the clutch was slipping.
I took the two STs to #Bashfest but sadly got very little runtime with them. The Red one with the Alpha engine worked flawlessly, but the radio gear had a very limited range (50ft Approx) so I need to get some replacement radio gear for that. The car in this video (the silver one) managed a Lap of the technical track before the Clutch/Diff gave out. I did have some footage of it, but the image was blurry due to a smudge on the Gopro.
The clutch was worn past the springs so was in need of replacing, however this didn't resolve the problem. The Centre Diff was slipping..
After unpacking from #bashfest weekend I decided to investigate what was wrong...