Cleaned the case then cracked open the 1974 A806 spare trans I have I want to swap into my 1974 A407 that stains clothes at times. Luckily there wasnt any signs of moisture and water inside. The oil was dark brown. Trouble was it literally was like Hersheys syrup. It was so insanely thick and gooey that the gas I was cleaning it with had trouble dissolving it. Finally got it all cleaned out and I was going to install the Sta-Lube 85W90 in it but I remembered the old oil looked just like the 500W oil I used to put in my Model A Ford trans and smelled like it too. Should I just go ahead and use the 85W90 or find the 500W?