Castrol Syntec

[eelman]

Any of you guys use this? I did my 10 hr change yesterday and used this oil in 10w30. The only confusing part for me was the lower unit change, It calls for hypoid 90 but I could not find that anywhere so I used Lubrimatic 80w90 hope thats ok! It says its for outboards and is high viscosity......

[Roger]

I don't think it hurts to use synthetic, other than some say it lengthens the time to fully break in the motor. FWIW, I use Castrol GTX in my 4s. Coincidentally, when I bought my oil filter, the mechanic also recommended that same oil. He must have felt strongly about it because I didn't ask for his advice.

I normally use Lubrimatic LU oil, and sometimes use regular name brand gear oil. Your owners manual will indicate the minimum API requirement for your crankcase and LU oil.

[fishaholic18]

Bill, NAPA has the 90 I think.