Re: Synthetic gear oil for transmission, transfer case and differentials
Agree with cruiserlarry. At 1000 miles, I switched to Redline 75w90NS in the manual transmission, and Redline 75w90 in the Torsen/transfer case, and both differentials. Redline 75w90 and 75w90NS are both GL-5 gear oils.
The transmission does shift noticeably smoother, though the transmission actually was very smooth with the OEM gear oil. It may be my imagination, but there now seems to be much less buzz/vibration in the transfer case lever. I haven't had a good test of gas mileage yet ... After the oil change, I inadvertently filled the tank with gasohol, which hurts mpg. I need to take a highway trip for a good test.
Unfortunately, Toyota is still in the dark ages. My invoice for the oil change states,
"Customer has been advised Toyota does not recommend synthetic oils.
Customer has been advised the warranty may be voided.
Case # TA061370169"