I recently did a transmission oil exchange and sent a sample of the old fluid to a lab to be analyzed. I have never had transmission fluid analyzed before and will not pretend to completely understand the lab report. In fact I am interested to hear from those with more experience on the matter concerning the report. I sent this sample in hoping that this would be a useful reference for other owners here to look at in case they are considering changing out earlier than the recommended mileage. Please note that the fluid was not deemed "Severe" but was rated "Abnormal." Tin, copper, and acid were found in excess and the viscosity may or may not have been up to the anticipated spec (not sure what it should be).
I had a Toyota Dealer conduct the exchange and I brought in Amsoil Signature Series fluid (Toyota WS compatible) that they replaced the original fluid with. I also had them drop and replace the mesh filter. For those that are interested, I was not having any problems with the vehicle or the transmission, it shifted smooth and have never had any transmission heating problems or lights coming on. Back in the 90's I had the transmission go out on an old accura and ever since then I have done drain and fills at 30k miles. I have had a couple 4runners that I also have done complete exchanges on when they get up over 150k miles. I usually take a minute to note the color of the drained fluid and let that be my (very un-scientific) guide on increasing or decreasing interval timing.
After the service was completed I did not notice any discernible difference in driving, shifting or gas mileage. This has not been the case with other vehicles that I have done complete exchanges with, they usually shift much smoother and seem to perform better. My conclusion from driving the LC leads me to believe that the service interval was not excessive. My conclusion from the lab report makes me wish I had changed it out earlier...
I had a Toyota Dealer conduct the exchange and I brought in Amsoil Signature Series fluid (Toyota WS compatible) that they replaced the original fluid with. I also had them drop and replace the mesh filter. For those that are interested, I was not having any problems with the vehicle or the transmission, it shifted smooth and have never had any transmission heating problems or lights coming on. Back in the 90's I had the transmission go out on an old accura and ever since then I have done drain and fills at 30k miles. I have had a couple 4runners that I also have done complete exchanges on when they get up over 150k miles. I usually take a minute to note the color of the drained fluid and let that be my (very un-scientific) guide on increasing or decreasing interval timing.
After the service was completed I did not notice any discernible difference in driving, shifting or gas mileage. This has not been the case with other vehicles that I have done complete exchanges with, they usually shift much smoother and seem to perform better. My conclusion from driving the LC leads me to believe that the service interval was not excessive. My conclusion from the lab report makes me wish I had changed it out earlier...
