19-21 Tundra (No Transmission Cooler) Miles Survey [OFFICIAL THREAD]

Hi Guys,

Please share this thread with other forum members.

Want to have a survey of some of the higher mileage 19-21 tundras without an external transmission cooler. The ultimate goal is to have objective data on whether or not a transmission cooler impacts transmission longevity in a tundra particularly.

Year:
Miles:
Transmission fluid interval:
Towing (y/n):
Towing Frequency:
Temp Monitoring (y/n):

Appreciate your participation!



Leaderboard:
1. 208k @Vito117
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5. 101k @shawn474

The leaderboard will be updated at least once a week.

 

2021
32k
No fluid change yet
Yes
10 times since new
No

 

Year: 2019 (Bought 8/22 as a CPO with 20K miles)
Miles: 32K-ish
Transmission fluid interval: Did Drain & Fill @ 30K
Towing (y/n): Yes - 5,500 lb. travel trailer
Towing Frequency: 8-10 times/yr.
Monitor temps: Yes, with HU & Maestro



Spiked after pushing it hard up a nasty grade coming up out of the desert.

 

Format:

Year:2021
Miles: 79,000
Transmission fluid interval: did a drain and fill at 50k

Towing (y/n): Yes
Towing Frequency: once a month, but it's a work truck, so alot of slow driving, loading up the bed. Idling ect.[/QUOTE]

 

There’s one guy on here with a 2019 that has over 200k that doesn’t have the cooler

 

Great, yeah I saw that earlier. Would be great if he could add his data to the thread. Any way to tag him in this?

 

I found the guy. @Vito117

 

Year: 2019
Miles: 101,000 miles
Transmission fluid interval: changed at 70k
Towing (y/n): y
Towing Frequency: utility trailer a couple dozen times a year. Camper (rpod now; Jayco hybrid 24 feet previously) about 5-8 times per year.

 

2019
92,500
Trans fluid not changed yet.
Tow horse trailer 5,000 lbs at least 20 times a year.

 

Trying to keep it simple for now, will add if we get more requests. Thanks for adding your data.

 

Year: 2021
Miles: ~101,000
Transmission fluid interval: one drain and fill every 10k
Towing (y/n): y
Towing Frequency: at least once a week.
Monitor temp: yes - never goes above 230°

 

Year. 2021
Miles: 31xxx
Transmission fluid interval: not yet
Towing (y/n): yes, 3500 lb boat
Towing Frequency: approx 25% of miles mix of short trips to launch, 100 mile trips, and 600+ mile trips
Temp Monitoring (y/n): yes

 

Year:21

Miles:16000

Transmission fluid interval:Will do 1st drain and fill at 30k

Towing (y/n):Y

Towing Frequency:
Once a month from NJ to VA

Temp Monitoring (y/n):N, but have already installed a Wholesale Automatics trans cooler, so I’m not that worried.

 

Sorry guys for late responses.
Year:19

Miles: 208,000 and counting
Transmission fluid interval: No flush yet, Checked at my 200K tune up..
Towing (y/n):Y
Towing Frequency: 1-2 times a month. Light loads. 40-120 miles
Trans cooler: NO

So do I have a freak truck or what?
No slippage, no odd sounds on the highway. Temps normal. Slight temp rise on a hot summer day towing a flatbed once.
My Toyota mechanic insisted not doing a total flush at my 200K tune up.

 

Awesome, thanks for the post Vito. Hoping to see more and more higher mileage tundras without transmission cooler.

If you know anyone else with similar numbers, direct them here, would help people rest easy with their stock 19-21 tundras.

 

Year: 2021
Miles: 88,300 today
Transmission fluid interval: huh? Nada, never touched
Towing (y/n): Y
Towing Frequency: 3-4 times a year, utility dump trailer w/ 2000-4000lb payload, ~40-60 mile round trip
Temp Monitoring (y/n): nope

I did have one event of the truck warning me about high transmission temps because I was a ‘tard and forgot to engage tow/haul mode. But no issues since…

 

Yep, have seen it earlier that not turning on tow/haul will get the sensor to go off.

 

Year: 2021
Miles: 53,850
Transmission fluid interval: Drain & Fill at 34,170
Towing (y/n): 5,500lb boat/trailer (~350lb tongue weight)
Towing Frequency: probably over 50x a year (isn't kept in water and we are out a couple times a week from April through November)
Temp Monitoring (y/n): Veepeak with OBD Fusion + Toyota Enhanced Diagnostics, don't think I've ever seen anything higher than 225-230°F

 

Year: 19
Miles: 90k
Tran Int: 30k
Tow: Y
X/Yr.: 25
Monitor: Y

Unable to maintain under 220 degrees when towing, even light loads, in anything other than S4, unless 45 degrees ish or under. When under 45 can get away with S5 and if really cold D. Tired of fighting it and watching temps, cooler going in very soon.

 

Manual says Tow in S4 with Tow/Haul on. S4 is 1:1 direct drive and makes for more TC lock up.

S5 and Drive allow your torque converter to unlock a lot more which creates heat.

Just an option to try before spending time/money on the cooler.

With the exception of a couple of very temporary temperature spikes on big grades, I was pleasantly surprised on a recent trip towing through the desert the my '19 in S4 settled in at about 210º

Definitely no downside to adding the cooler, but I'm thinking for my uses it may not be needed. I can do quite a few 30K drain & fills for what the cooler would cost.

 

Great to hear, will check my temps next time I tow.

 

Good info Surfer.
Now I know why the nifty sorta manual shifter thing is there . I figured it was to impress the women!

 

Says the guy with 208,000 miles and no transmission problems in his '19!

Well in my first truck, ('78 Datsun PU w/bench seat and 5 spd manual) when I had a pretty girl sitting in the middle I probably shifted WAY more than necessary!

You couldn't help but accidentally touch her leg a little.

"You know, it'd probably be more comfortable if you just put one leg on each side of the shifter, that way you're not sitting all twisted up."

 

Stock truck, I guess? Mine was way up, even in 50F weather, never towed anything. 33" LT tires, steel bumper + winch, steel skids all the way to transfer case. Wife's V8 Sequoia seems to be fine, even with similar skids setup.

 

Ha! Yep.
First truck of mine was a 1989 Izuzu Pup 4X4- 5 speed manual. Truck was pretty indestructible and had it for 12 years. Until I let some asshat borrow it and he burned the clutch out in one day.

 

My 2019 manual says to use S4 when using engine braking to maintain charging system performance. Inference being D is fine otherwise, ie: on a level freeway, according to my reading of the manual. I am aware of the S and D options and S4 is the only one that always works for temp control. So I almost always tow in S4 and it mostly stays under 220. I also monitor TC lockup. On level ground once up to speed S4, 5, 6, & D all run locked up, with tow haul engaged. But usually have a big difference in temp. I also monitor engine load, it is always the lowest in S4, which is likely why it has the best towing temp performance.

Glad you have a cool running one, many or even most do not, so getting a cooler it is for me. I initially was not going to do it, but after more monitoring and deciding to keep this truck to 300k+, cooler made sense. There is a thread here someplace, a few years old, where a couple of us gave detailed towing temp readouts under various situations. My conclusion is occasional towing of moderate loads no cooler needed. Tow often or in warmer weather, either heavy or bulky loads that catch lots of wind, cooler is a good idea.

 

The thread I referred to is:https://www.tundras.com/threads/green-thunder-oil-analysis-thread.94464/

Also forgot to mention off-road in 4WD really spikes tranny temps too. That pretty much clinched to cooler issue for me as I do lots of off-road stuff and would often like to be in 4 hi, but can’t as currently set up.

 

Yeah, that's the other thing I was watching for on this recent desert trip since I got to play in the dirt a little.

Some of the stuff I would've probably preferred to run in 4HI but just kept it in LO as I knew it would stay cooler. Plus it kept me from going too fast since we had the pups along for the ride.

Sounds like you've educated yourself well on the whole deal, I only brought it up because many people have not.

Depending on what I see when I continue to monitor temps I may eventually add the cooler, just don't want to spend the money if I don't have to... So far I'm feeling like it may not be necessary.

 

Prior to me adding a cooler to our 2020 Tundra:
Year: 2020
Miles: 45,000
Transmission fluid interval: Half changed at 40K
Towing (y/n): Y
Towing Frequency: Around once a month
Temp Monitoring (y/n): Y

Thermal degregation number was ~3,000 when prior to me installing a cooler (I was surprised it was this low). Installed a cooler at 45,000, as of 71,000 miles, I'm around 3,500 on the thermal degregation number.

Obivously don't include this in your data points (since you want 19-21 Tundras), but here is our Toyota Sequoia without a transmission cooler:

Year: 2014
Miles: 103,000
Transmission fluid interval: Half changed at 100K
Towing (y/n): N
Towing Frequency: Almost never
Temp Monitoring (y/n): Y

Thermal degredation number maxed out on the Sequoia. However, transmission shifts as smooth as butter, temps in the 220's mostly.


The reason I installed a cooler was touched on by another poster, but our Tundra is 4x4 and on Hi, it definitely pushes the temps up. Plus we tow enough that I wasn't comfortable with the 240+ temps I was seeing. My biggest gripe about the 19-21's is that the sticker said there was a cooler and didn't have one.

 

A local electrical contractor up here in northern Manitoba has a fleet of 6 Toyota Tundras 2016-2021.

Some have over 450,000km, they all tow heavy loads daily and operate in very harsh conditions.

None of them have ever had a transmission oil service or flush and none have had any transmission issues.