I posted before that my 2nd syncro's is messed up. Today, I found out that the Gear Oil I used was to heavy (80W- something). According to a manual I'm suppose to use 5w-30 motor oil. They told my this is because the gear oil is way to thick and the syncro's dont work as well. Can somebody verify this by experience or can somebody verify on their manuals??? And if yes, how many quarts do I buy?? Should I use full synthetic oil? Thanx