so I'm wondering if this section can be disassembled and regreased? As I said further up, it seemed that spraying lubricant on to the UJs had some effect but I always wondered if it was placebo since it no longer seems to have any effect.....and I'm not aware of any grease or lubricant that goes hard at temperature then softens up again when it cools?? It either liquidises and drains away, oxidises (grease is just a carrier for the lubricating medium, not a lubricant per se), or hardens permanently....its just damn weird and I wish BMW would just come clean. But having worked extensively with German tecchies in other industries, I know that admitting they got it wrong is not something they do well!
High-temperature effects. High temperatures harm greases more than they harm oils. Grease, by its nature, cannot dissipate heat by convection like a circulating oil. Consequently, without the ability to transfer away heat, excessive temperatures result in accelerated oxidation or even carbonization where grease hardens or forms a crust.
Effective grease lubrication depends on the grease's consistency. High temperatures induce softening and bleeding, causing grease to flow away from needed areas. The mineral oil in grease can flash, burn or evaporate at temperatures greater than 177°C (350°F).
