AT Drain and Fill - 2018 Tacoma

The transmission / torque converter shudder on my 2018 Tacoma is getting worse so I'm going to do a drain and fill. My local garage is doing this for me. It's a good garage that I trust more than my dealer.

Question - Is it necessary to pin the transmission cooler thermostat open?

I've watched a few videos and read a bunch of threads on the topic but I don't have a clear answer on whether it's necessary on my 2018.

I had the garage check the driveshaft u-joints. All are good. And my mechanic used his scanner to see what the truck is doing when the shudder happens. No misfires recorded. Hopefully the drain and fill fixes the shudder.

 

The pin is only relevant if doing a full flush to get all the fluid out. A drain and fill doesn't require messing around with it.

 

You dont know if you are low on fluid to begin with, so a drain and fill with the same amount would still leave questions.

 

Yes, pin the thermostat. Here is old Tundra procedure that calls for it. Not sure why Tacoma procedure does not mention it

 

I pinned mine on my 2018. I did several drain and fills. In between each one I idled the truck and ran through the shifter a couple times. I put in 12 qts of Redline so I got a good % exchanged and it was nice to know my fluid level was good.

 

unless you have already addressed it, while up on the rack have them shine a light on the coolant crossover pipe behind the motor. passenger side you can get a visual on the pipe where it connects to the motor. look for pink corrosion.

 

Thanks for replies folks. Got it done. Fluid looked clean coming out. Surprised at how clean it looked actually.

Transmission shifts are much, much smoother now. The torque converter shudder at low RPMS is also not as bad. At low speeds and RPMS, the transmission will shift down a gear much sooner and before the shudder gets a chance to happen. It's not totally gone but a big improvement.

I think I will do another drain and fill next week to see if it improve things more. And I'll a look at the crossover pipe then. Thanks for the suggestion.