3rd Gen Automatic Transmission Fluid Level Check DIY

https://www.ebay.com/itm/Toyota-Lex...345970&hash=item33dbdb8b0a:g:AFkAAOSw8b1aGFbV

Has anyone used one of these kits? Seems like it would make life a lot easier!

 

rowsdower, thanks for such a great write-up, it made checking the tranny easy. have a 2018 taco sport, bought second owner 20,000 kilometers, checked the rear diff - down 1.2 liters; checked the front diff - down .5 liter; checked the transfer case - surprised actually full; checked the tranny - down .25 liter. anyone that buys a vehicle, new or used, and doesn't check the fluid levels in all the cases is asking for trouble down the road.

 

So I drained the overfill plug until it basically was dripping past the trickle. Did I drain too long or is this sufficient?

 

As long as you were still in the prescribed temperature range, you should be good. You should have a good flow to start, indicating you've put enough fluid in, and then it will stop/trickle once the right level is reached.

 

So I've read the post about Tacomas coming from the factory with low ATF. Most posts indicate that the transmission is anywhere from 0.5-1 qt low on ATF. Thus, most people are adding roughly 1 qt to "top off" their fluids.

What is confusing me is the temperature window requirement; if the truck is isn't moving, there is not going to be any heat being generated in the transmission. If this is the case, then isn't the truck is simply reading the engine thermostat? Fluids also do not expand significantly with changes in temperature, so it really shouldn't have any bearing on the reading.

So I guess what I'm getting at is, does adding this fluid actually do anything or is this fluid you're adding simply draining back out of the overflow valve? This entire process doesn't seem convincing unless somebody measures the amount put in and the amount that drains out.

 

How do u think people came to the conclusion that they were a quart low? They added a quart and a few trickles came out once they pulled the overflow.

 

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Have you checked yours? I would check mine but only if somebody next to me who's done it. Not ready to "blow my tranni" yet...

 

Original post says you should see a "gush of fluid" when opening the overflow. If being a quart to half a quart low is so detrimental to the life and performance of the transmission, then similar caution should be taken when filling it. Adding a quart, and seeing some fluid drain out means nothing more than "I added extra fluid". Nobody has actually mentioned how much fluid truly should be in the transmission, it is all seems speculation. If you look at it from an engine oil standpoint, I can add a whole extra 3 or 4 qts past full. Yeah, now I have an engine full of oil, but it is overfilled and it is damaging over time. Using the same argument, if my dipstick shows my oil level is between the 2 lines, I'm not topped off, but my oil level isn't low.

 

A couple of laps around the block will help to warm up your transmission so that it’s close to the temperature check range.

Of course this has been discussed in TW many times. Months ago, I calculated the expansion of the approximately 10.7 quarts of transmission fluid contained within the Tacoma transmission and from ambient temperatures of around 70 degrees up to operating temperatures of around 190 degrees or more, the total capacity only expands by several ounces.

So, you’re correct that it’s probably not too critical to be at exactly the range stated for the check. A few degrees above or below it isn’t going to make that much of a difference when checking the level.

The added fluid can make a big difference, especially if your transmission is clunking when shifting from Park to Reverse or from Reverse to Drive. Mine was clunking heavily when at 200 miles from brand new. I added 1 quart and the clunking was gone.
I later checked the level by opening the overflow and only a few ounces came out. I measured it, although you don’t need to measure it.
Accounting for the small amount that was left in the drain pan and also on the funnel after pouring it into a measuring cup, I estimated that my transmission was about 28 ounces low.

What you’re doing when you’re checking the level and adding fluid to the transmission is overfilling it to above or over the top of the overflow drain hole which is above the pan drain plug hole.
When you remove the overflow plug, mostly it’s the amount of fluid above that drain hole that is draining out, and then an additional trickle which is fluid vibrating out from turbulence at the surface of the fluid.

If your transmission is 1 quart low (just a guess) and you add only 1/4 or 1/2 of a quart, you still wouldn’t know how low it is as the small amount added wouldn’t flow out of the overflow.
Hence the need to overfill the transmission to check and correct/adjust it to the proper level.

I can’t remember the exact temp, but I checked my level at around 103 to 105 degrees or so.
It’s possible that in many areas of the U.S. during the Spring and Summer you’ll be close to the proper check temp just from ambient air outside and/or heat off of pavement at mid day.


Measuring capacity of stock and aftermarket fluid coolers, just for the heck of it.

 

You have no idea how transmissions work, yet you're digging your heels in like somehow the diy is wrong or that your points are valid. You're comparing apples to oranges. Learn what the diy is actually saying then if you have any real concerns ask away.

 

Thanks for taking some measurements. It is much more convincing if somebody backs up what they've done. So the assumption is that the overflow valve is more or less the ideal fluid level in the trans? That would make sense.

I guess my comparison wasn't great. All I want is some evidence that this actually does something before I potentially damage something. Trusting a few posts on TW isn't what I would consider great evidence.

 

Which is exactly my point. You're looking for some kind of validation or consolation that this is safe, or necessary, research how overflows work on a transmission and it'll alllllllll make sense.

 

Will do, thanks bud!

 

I’ve never removed a Tacoma transmission pan, but have done it on other vehicles. So, I don’t know if the Tacoma has an elevated tube, or whether it’s just a drain hole.

This is just to show how an overflow works and for those who have never done a fluid check before, to visualize what is being accomplished with the procedure.

The sketch shows that there is only one level that is correct.
As the Tacoma has no dipstick, the only way to get to the proper level is by overfilling the transmission and then removing the overflow plug until fluid just trickles out.
It’s difficult to get it wrong!

 

Thanks @rowsdower just completed this yesterday I was only about 1/4 low nothing too concerning but it’s peace of mind that the oil is at a proper level.

 

@rowsdower thanks for taking the time to write this. I was just under 3/4 quart low.

 

What temp (with scan gauge) are ya'll checking the fluid level at?

 

First of all big thanks to the OP for an excellent directions and pictures!

Sooo, instead of "install TRD parts" day I decided to make it a "check and replace all fluids" day. Not going to get into details of the procedure but here are my results/findings:

For the record I have a 2019 DCSB OR 4X4, build date 11/2018, as of now 4k on the clock.

Rear differential: Drained 3.5 qt, pumped in 4.2-4.3qt, 0.7qt low!
Front differential: Drained 1.1qt, pumped in 1.6-1.7qt, 0.5qt low!
Transmission: Added 1qt, drained out 0.75qt, 0.25qt low!

The only thing I didn't check is the Transfer case. Couldn't find straight 75W oil. Not even Toyota dealer had one. So now it's official, 2019 are running low too, f%^$# dealers, can't even do the work they're getting paid for.

 

What if I just went and put a half a quart in and called it a day? Assuming I was perfectly filled to begin with and overfilled .5 quarts, I doubt that would be harmful, no?