In 2020 Mike Sweers and the powers that be at Toyota decided to remove the external transmission cooler on the very old 6-speed used in my Tundra. Although I don't fully understand the specifics, I believe this change had more to do with a change in the AC system which somehow necessitated removing the external cooler. Weirdly, you can add an external aftermarket cooler without any issues. Mike and his team claim they tested the transmission without the external cooler and all is good! Except, I don't believe him, at least not in all cases.
They made no further changes other than a very small hockey puck size "heat exchanger" that attempt to warm and cool the transmission fluid by exchanging heat with the engine coolant. It's still the same WS fluid. They still claim it's "lifetime fluid". There were no internal changes made to the transmission. So from 2007 until 2019, it was needed but magically now it's not needed? Every other pickup or vehicle with a tow package uses an external cooler but my Tundra doesn't need it? Interestingly, ALL other large vehicles that used the same 6-speed continued to use an external cooler but now my Tundra doesn't need it?
I'm not too worried about my truck as I don't tow BUT I plan to refresh the fluid every 50k miles. My transmission routinely reached 225F on flat highway, unladen, cruizing at 75mph. Not super hot but warmer than I'd like considering there is no load and it's well-known heat kills transmission fluid over time. There are quite a few stories of 2020 and 2021 transmissions overheating while pulling a load well within the tow rating. There are stories of the transmissions overheating simply doing a slow crawl up long hills or while going uphill in reverse. Prior to 2020, these stories are very sparse.
Mike Sweers is on record stating there is no problem. I have repeatedly goated him on social media (and interestingly) he will reply stating there is no problem. I don't believe him. There are dealer techs on record stating if it was their truck and they towed they would add the external cooler. There are dealerships that will add an aftermarket external cooler kit no questions asked.
Now here's my point. Maybe I'm totally wrong and Mike is spot on and these transmissions will go +250K miles but with how poorly many manufacturers have engineered and tested vehicles in the last decade and with how many recalls and attempted coverups or complete reluctance to fix problems when there is clearly an issue, I just don't trust any manufactures anymore. Is it just a lack of expertise? Is it just cost-cutting above all else to maximize profits? Some combination of both?
They made no further changes other than a very small hockey puck size "heat exchanger" that attempt to warm and cool the transmission fluid by exchanging heat with the engine coolant. It's still the same WS fluid. They still claim it's "lifetime fluid". There were no internal changes made to the transmission. So from 2007 until 2019, it was needed but magically now it's not needed? Every other pickup or vehicle with a tow package uses an external cooler but my Tundra doesn't need it? Interestingly, ALL other large vehicles that used the same 6-speed continued to use an external cooler but now my Tundra doesn't need it?
I'm not too worried about my truck as I don't tow BUT I plan to refresh the fluid every 50k miles. My transmission routinely reached 225F on flat highway, unladen, cruizing at 75mph. Not super hot but warmer than I'd like considering there is no load and it's well-known heat kills transmission fluid over time. There are quite a few stories of 2020 and 2021 transmissions overheating while pulling a load well within the tow rating. There are stories of the transmissions overheating simply doing a slow crawl up long hills or while going uphill in reverse. Prior to 2020, these stories are very sparse.
Mike Sweers is on record stating there is no problem. I have repeatedly goated him on social media (and interestingly) he will reply stating there is no problem. I don't believe him. There are dealer techs on record stating if it was their truck and they towed they would add the external cooler. There are dealerships that will add an aftermarket external cooler kit no questions asked.
Now here's my point. Maybe I'm totally wrong and Mike is spot on and these transmissions will go +250K miles but with how poorly many manufacturers have engineered and tested vehicles in the last decade and with how many recalls and attempted coverups or complete reluctance to fix problems when there is clearly an issue, I just don't trust any manufactures anymore. Is it just a lack of expertise? Is it just cost-cutting above all else to maximize profits? Some combination of both?
