Reply to "ZF Dash 2 Transaxle Gear Lube"

Synthetics are always iffy in our 50-year-old ZF design. Some synthetics swell certain synthetic rubbers while others shrink them. The shrinking causes leaks while swelling only softens the sealing parts, but the assembly carries no internal pressure so it seems benign. If you found a synthetic by experiment that doesn't leak, good.
Temperatures inside a ZF under HARD driving do not seem to exceed 180F by my measurements (plus a few racers)- hardly enough to chase out condensation. So 'high-temp' lubes or diff- coolers are not needed this side of the Daytona 24 or LeMans 24.
LSD additives are needed only if your ZF chatters in turns- as the thread-starter here had. Chatter shock-loads all the gears engaged and is best avoided for longevity.
Blending different lubes for any reason is an un-good idea. See this month's POCA Newsletter on the effect of additives in motor oils to 'adjust' ZDDP levels, and what it does to the load-carrying properties of otherwise good oils.
As for metal compatibility with diff lubes, there are no brass/bronze parts in ZFs that I've found; everything is high-alloy steel: the synchos are all-steel as are the few thrust washers and the cases are aluminum.