Glad to see another Aussie from Sydney here. I think you are onto it with mention of a vacuum problem, especially given two problems coinciding with fitting the vacuum reservoir. Vacuum problems could interfere with both transmission operation and crankcase ventilation.
Have you considered joining the Mercedes-Benz Club of NSW? Our next meeting is next Wednesday night, August 6 and one of our major events for the year, the concours is coming up on September 14. Like minded enthusiasts and access to workshop manuals in the club can also help sort problems with your car.
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.