I just had a new tranny put in under warranty about 1700 miles ago. I wanted to dump the toyota fluid after a break in and after doing some research. Here is what I came up with.
The Holden and GM cars that run this tranny shed a lot of light on this. Everything points to the oil that toyota uses and misinformation by guys swaping in new oil.
Our trannys need a GL-4, 75-90, synthetic oil. NOT A GL-5, NOT SYNCROMESH. GL-5 is not yellow metal compatible, and syncromesh provides zero heavy load and shock protection on bearings and gear faces. This is all because the syncros require just the right amount of friction to work perfectly and still be protected. GL-5 fluid will corrode our yellow metal syncros. A regular gear oil with additive, super lubricant, or friction eliminator package will also not fit the bill.
The Holden Commodore driver seem to like the Amsoil and have had good luck with it. Here is why, Amsoil MTG specifies all of the following.
-GL-4
-yellow metal safe
-75-90
-synthetic
-improves syncro operation
These are all of the keys to long life in our trannys, per Aisin, per GM, and per Holden. So this is the route I went. I just dumped my toyota fluid, with only 1700 miles on it. It looked like garbage, lots of metal on the drain plug and already a burned smell. My shifts were still ok so I had zero tranny issues to start with on the Amsoil MTG. 2 quarts of Amsoil later and it feels amazing. Better than my first tranny ever did and better than this new one felt with stock fluid.
My plan now is smooth shifts, slow cold engine shifts, and change the tranny oil at 15,000.
I think are trannys can be ok. They're not perfect, but I think a lot of these failures are from incorrect fluid, abuse, and just horrible clutching.
This is just my research, my 2¢, and hopefully some helpful info.
The Holden and GM cars that run this tranny shed a lot of light on this. Everything points to the oil that toyota uses and misinformation by guys swaping in new oil.
Our trannys need a GL-4, 75-90, synthetic oil. NOT A GL-5, NOT SYNCROMESH. GL-5 is not yellow metal compatible, and syncromesh provides zero heavy load and shock protection on bearings and gear faces. This is all because the syncros require just the right amount of friction to work perfectly and still be protected. GL-5 fluid will corrode our yellow metal syncros. A regular gear oil with additive, super lubricant, or friction eliminator package will also not fit the bill.
The Holden Commodore driver seem to like the Amsoil and have had good luck with it. Here is why, Amsoil MTG specifies all of the following.
-GL-4
-yellow metal safe
-75-90
-synthetic
-improves syncro operation
These are all of the keys to long life in our trannys, per Aisin, per GM, and per Holden. So this is the route I went. I just dumped my toyota fluid, with only 1700 miles on it. It looked like garbage, lots of metal on the drain plug and already a burned smell. My shifts were still ok so I had zero tranny issues to start with on the Amsoil MTG. 2 quarts of Amsoil later and it feels amazing. Better than my first tranny ever did and better than this new one felt with stock fluid.
My plan now is smooth shifts, slow cold engine shifts, and change the tranny oil at 15,000.
I think are trannys can be ok. They're not perfect, but I think a lot of these failures are from incorrect fluid, abuse, and just horrible clutching.
This is just my research, my 2¢, and hopefully some helpful info.
