Transmission fears sadly confirmed...

As a Toyota fan, I put my faith in the "Engineers" over "profiteers"....and it all showed up on a desserted island in 4hi, towing a 3000lb+/- trailer on the beach....


Yep, transmission fluid temp warning light!!!!

Guess who is all in now on, get a transmission cooler. And by the way, when it get hot, it smells...and, btw, when it gets hot, it doesn't change gears well or have the torque you want.

Luckily, the light came on at the same time that I was "parking" on the beach campsite. But this is a dependability problem. This is a severe issue, and I confirmed it.

If you were like me, thinking engineers know what's up.....I never, ever thought this would be a concern....welp, get a cooler.

I'm on team cooler. GET A TRANS COOLER... And in reality, Toyota needs to pay for it.

 

4LO might be better for towing on the beach.

 

Your issue is in bold. 4 hi is for driving normal speeds in 4x4. Slow speed should be done in 4Lo. This keeps the torque converter locked up more and helps keep transmission pan temps lower.

Moving low speed, in sand, AND towing while in 4hi is bad juju. This might have even been enough to overwhelm a cooler, if you had it installed. The cooler is dependent on airflow through the grille, and a large portion of that is dependent on speed. The fan can only do so much.

Adding a cooler will keep you cooler for longer, but there's no guarantee that it can overcome these conditions. Take this info to Toyota, and I'd bet money they'll tell you that operator error was the cause and show you the door.

 

Not might be better; absolutely would be better.

 

Can confirm cause I was an idiot and did the wrong thing…climbing a rocky mountain access road with buddies and was in 4HI….about 5 -8mph and you guessed it….high trans temp even with a factory cooler (08) and that was right after my drain and fill at the dealer at 120k. *facepalm*. Got about halfway up the mountain and realized my idiotic mistake, stopped for a while and let it cool a bit and then got shifted to 4L and it cooled off immediately and stayed cool the entire rest of the day. My mistake! Now….that being said I know this is about you having a 2020 with no trans cooler, I just figured I’d share my boneheaded mistake

 

100% your own fault. A transmission builds heat when it's slipping, I don't care how huge of a cooler you have. I did the exact same thing a year ago, on the beach and was too fucking lazy to air down and "I have the horsepower", well that lasted 15 minutes and then roasted the trans and that was with a cooler.

 

Welp, never too old to learn something. Been driving on the beach 20 years, been towing my camo trailer for a few years, never an issue. But...all this makes sense, guess it's 4 LO when we pull outta here tomorrow

 

Don't forget to swap that cooked fluid when you get back.

 

What's make sand so hard on the trucks is it from the tires spinning? If you don't air down enough? And what's top speed of 4lo? I always wanted to go to Glamis or any other dunes but from the videos I see there going faster than 4lo could offer? As you can probably tell I have no experience in sand or the beach except for daytona and that was hard as pavement

 

Sand is loose, so you will sink into, and this is going to create more rolling resistance. Think of it the same way you would if you were walking. Is it easier or harder to walk through sand that you sink into? That added effort you have to put in is similar to what your truck will have to do. Working harder is a given when going through loose stuff because of the rolling resistance/friction that has to be overcome.

Airing down is to let the tire squish out to the sides and increase the contact patch of your tire. It's like putting on snow shoes, and is going to help you to sink less.

The OP needed to be in 4Lo because of the slow speeds, not because they were in sand. The general rule is that if you need 4WD and you are going to be going slow you use Lo to avoid overheating the transmission. If you are going to be travelling at speed and need 4WD then you are going to use Hi. Running dunes at speed you would be in 4Hi, not 4Lo. On the beach there are people, other vehicles, etc. and you are going to drive slowly, so you need to be in Lo.

 

Perfect thanks, that makes perfect sense, now once I get out there someday I won't smoke my tranny

 

Best bet for info and tips is going to be getting a hold of people that do it on the regular, and ask them for guidance.

 

Is it just speed dependent, or also load dependent? Would 4hi at low speed be fine if OP wasn't towing a trailer?

 

It wouldn't heat up as quickly, but load isn't just the trailer. "Under load" just means making the vehicle work and can include towing, loaded with gear and/or passengers, going uphill, driving on any surface with increased resistance, etc.

That's why the general rule is that if you are going slow and using 4WD use 4Lo. You're not going to hurt your truck using 4Lo unless you start trying to go too fast.

 

It really is funny....I've spent my whole life riding the beach, hitting mountain trails.....the beach has always been 4hi, the mountains were 4lo. I'm also all about making it easy on your rig. With 37s and 35s, I still always air down...doesn't matter about power or tire size, make it easy....

I just never even thought about 4lo....a forehead in hands moment.

Thanks Tundra forums for the help

 

Everybody learns at different times. Honestly, I probably would have done the same just a few years ago. I never even thought about transmission heat with my last truck.

 

A guy on T4R had this happen to a new 2021 slow crawling up a trail pass in 4 hi. The 4runner has an old school in tank cooler and I can confirm it keeps the A750F trans ice cold. It still hit the 302F warning light temp.

 

There's a TFL truck video where they took a new 6.2 silverado up a mountain with a trailer, but were going slow. This wasn't an Ike gauntlet run. Would putting the system in 4LO fix it then, forcing the torque convertor to lock more?

Really I'm trying to understand what the max speed for 4Lo would be. Anything under 30mph? 20?

https://youtu.be/8OX98vv7jmA

 

You'd have to check your manual as it'll vary by make and model. It may not even list it in the manual.


To go into 4Lo you have be stopped. Start driving, and see how the truck responds. Don't push the RPMs to crazy, and just see how it feels. I imagine anything over 10 MPH will not feel right.

Don't get hung up on speed. You can always go slower. Let's say you want to go 15 MPH, but you know that's not good for 4Lo, and you are afraid of overheating in 4Hi. Then don't go 15 MPH. Go 8 in 4Lo. Problem solved.

 

Yep. I was trying to be gentle with the guy.

 

Ah, I see. I mistook your gentleness for a bit of uncertainty. My bad.

 

These threads are great for noobs like me. Thank you all.

 

yeah this thread cracks me up for all the years I off roaded at low speeds in my 04 tacoma in 4hi. Never had any issues but I'd imagine the transmission was not happy with me, and hopefully the current owner of it hasn't had any issues...

 

My car in 4-Low sounds like a weak or overloaded meat grinder ... I don't think I want to go over 10mph but I noticed it upshifts at least 2 gears from start (0mph). Something like 1st, 2nd then 3rd gear but I've never gone faster than ~8mph with it.

How many gears are there in 4-L?


changing subject:
I've read on the internet that the torque converter will lock even in the 3rd gear if the transmission temp goes above certain limit (something like 250-270F ?? Not sure).
If that is true, and if you are going fast enough to be in the 3rd gear (4-Hi or not) then the TC should lock before the trans temp goes too high and get a warning light.
Is that (the locking thing in 3rd) true?

I'm aware that while towing on the beach, your speed may not be high enough to be in the 3rd gear ... so this condition (locking in 3rd to prevent ATF overheating) may not apply to the OP ... but it will be nice to know if we can trust the internet or not!

 

Sorry to hijack thread (newbie lurking and reading these threads) but what about while in 4lo on the beach making turns. I've read somewhere in the forums that it may not be good on trans when in 4lo. Do you engage 4lo to 4hi or 2wd when making sharper turns or leave it in 4lo?

 

I would still leave it in 4 low on the sand even when turning. Damage from the Diff binding can occur on surfaces that don't allow the tires to spin independently, like on dry pavement. My 2cents of course.

 

4LO or 4HI is alright on any surface that has “give” to it. 4LO is preferred in the sand since sand presents such a load to your engine and transmission. The low range gives your transmission a mechanical advantage.

 

If it's packed sand low psi tires with 2wd or 4hi is OK? Vs looser sand 4lo

 

You are fine in packed sand as well. You are even fine on dirt and gravel roads.