Transmission drain and fill

I’ve been watching a lot of videos on how to do a transmission drain and fill. Every videos show that 2018 and up you have to bypass the transmission cooler thermostat. I have a 2019 SR5 4x4 and I can’t find one. Mine looks different. What am I missing?

 

I believe starting in model year 2019, Toyota eliminated the transmission cooler on the Tundra… therefore, no thermostat to bypass. Not a favorable design change imo, but hey what do I know.

TFL truck ran an Ike gauntlet with a late model 2nd gen without the trans cooler to test temps, etc… but I digress.

Point is, you’re not missing anything, because your truck likely doesn’t have a thermostat to bypass.

 

Thanks for that information. Would you happen to know if it’s still safe to do the transmission drain and fill myself? I haven’t seen a video without doing this step.

 

I am at 50k miles on my Tundra, so I have yet to actually hit the mileage interval to do a drain and fill on my truck just yet; I plan to do it at 60k miles. But, with that said, I would assume you can remove the step of bypassing the thermostat in our case because it is not present, so you don't run the risk of it throwing off your fluid level. To my knowledge, all the other procedures should be the same, with the exception of that one step.

I will add to all this that I am not a mechanic; I just perform basic maintenance on my own vehicles, so I am not an expert by any means. Perhaps a member who has done a trans drain and fill on a '19+ can chime in to confirm or disprove the above.

Not sure if you have looked at the Car Care Nut channel, but he has a process to check fluid level in Toyota trucks without a scan tool, since the fluid fill level is temperature-dependent. And as a Toyota owner, I generally like most of his content.

 

Yeah he is who I watch to do all my maintenance. I actually have a scan tool that has the AT temperature. I’m just a little paranoid lol. I’m a rookie DIYer. The dealership wanted to charge me a arm and leg.

 

2019-2021 do not have a transmission cooler, there is no thermostat to bypass. Just drain and fill like in the videos and disregard the portion related to the thermostat bypass. Everything else is exactly the same. You will be good

 

Thank you, just wanted to be sure.

 

100% correct. This bothered me as well on my 2019 so downloaded the Toyota manual and yes, just ignore the part of pinning the thermostat. Finally, a plus to Toyota removing the transmission cooler. Next, they will remove the engine from us and tell us it makes changing the spark plugs super easy.

 

I think on drain and fill, pinning the T-stat isn't done? Just replacing the fluid in the pan? If it is pinned, and just a drain and fill is done, there would be air trapped in the lines and cooler ?

 

The air is fully displaced with ATF the next time t-stat opens.

 

That would then mean the transmission fluid level is low?

 

No. ATF level is set with t-stat pinned on a running engine. With engine shut it largely drains back to sump.

 

This is a fluid change, not a drain & fill as was initially stated by OP.

 

Drain and fill is a fluid change With or without t-stat pinned you pump the same amount you drained and you'd be good. With t-stat pinned you just replace a bit more, and transmission won't have any problems displacing any air in lines and cooler. It does it every time on start.

 

WAIT! My tundra doesnt have an thermostat or tranny cooler??? Arent I going to fry my tranny???

Sorry, i just couldnt help myself. LOL

 

I was getting 230F in 50F weather just driving for 20 minutes on a freeway (50-60 MPH). Doing drain&fill every 20k miles, the fluid does look burnt and brownish. Not sure why it was so - wife's Sequoia had it well under 190 F even in hotter weather, climbing up some severe elevation at higher speed and having a roof basket loaded with camping gear. Both have skids up to the rear cats. It seems like if my slightly bigger and heavier 33" LT tires contribute to all of that heat. So I decided to retrofit a cooler, since I do occasional winter driving in deep snow with MPG numbers dropping to 1-3, which means torque converter generates a lot of heat.