Proper fill level on rear diff, front diff and transfer case?

Is the proper oil level even with bottom of fill hole or some distance (ex. 1/2”) below? Also has anyone had their automatic transmission fluid level be low in a new truck from the factory? Back when Gen 3 came out (2016), some new trucks with tow package were under filled from factory. I checked mine properly and it was filled correctly. Now with no external auto trans cooler, I was curious if the factory was routinely filling them properly?

 

I believe the official level on diffs is a few mm below the bottom of the fill hole (maybe it’s anywhere from 0-5mm?) but that is hard to measure. Most just go until they overflow out of the fill hole, let it level out and call it good.

On the trans it’s best to verify, haven’t seen any correlation that the deletion of the external cooler has changed the way they fill them.

 

Thanks. I used the “jumper” method in the OBD pin locations to check ATF on my 2016. It worked fine. I sold my 2016 and have a deposit on 2023. I’m driving 3 hours to a dealer to pick truck up. I won’t have the ability to check ATF until I get home. I’m assuming as long as I don’t get an ATF temp light , on drive home, there is little chance of damaging ATF?

 

You’ll be fine.

 

With the sealed transmissions, there is a stand pipe drain plug and a drain plug on the pan.

Jumping the pins as you spoke of simply lets you know when the trans temp is up to temp to be able to check the fluid level.

Checking level is done with the stand pipe plug, or overflow. Once the temp is up to 115*F but not over 130*F, the overflow plug is removed. Fluid level is correct when the fluid flows out, then slows to a slight trickle or stops.

 

Not understanding why you have a perception that the risk level is so high. Nothing is perfect of course, but if I’m understanding correctly you’re picking up a new truck and you’re concerned trans fluid level might be so low from factory fill that that you’ll damage the trans on a 3 hour drive home.

From that perspective your wheels could fly off, your engine and diffs could grenade from low oil, your tailgate could fall off and kill the driver behind you, etc.

You have a warranty. When you get home if you wish to check all fluid levels, you could document with a video in case there’s an issue, and go from there. On the other hand mucking with your transmission fluid takes you outside the recommended maintenance…

The probability of a factory fill issue so bad that’ll it’ll cause damage on the drive home is present, however it’s extraordinarily low, to the point of being not worth your concern. Otherwise, pointless to even get out of bed in the morning.

Enjoy your new truck!

 

I think he thought they were filled too low.
I’ve heard of them being low with the external cooler. Thought process was additional fluid wasn’t added on models with the cooler.

 

Saw your post in the other thread...
This is not an FJ; might want to get model specific and current on your info.

Temp check is 95°-113°F and OBD jumper method doesn't work on a '23

 

Of course it isn’t an FJ
Who would accomplish this without the service data? My post was an explanation. I wasn’t quoting the manual, thanks for highlighting my oversight

** And the temp range correction

 

You'd be surprised...

 

I really should have thought about that.

That’s what’s great about this place. A person can be corrected without being belittled.

 

I’ve read tons of 3rd Gen threads with owners checking/replacing fluid for the first time after 30k, 60k etc and having to add fluid beyond original to get to full. So it’s a “thing”. But what’s the probability, especially specific to a 2023? And what’s the impact of an underfilled tranny over a 3 hour drive?

If there’s real concern, write into the contract a transmission fluid level check, or outright pay for one, only way to mitigate the concern and drive away with a known situation.

 

What good would that do?

But again, you'd be surprised...lol.

 

I asked my dealership to check my transmission fluid level and they told me it was “impossible” because it was a sealed unit.

It does seem challenging, but I guess I have to do it now.

 

Yeah, I hear some of you guys talking about “the warranty”. Yes there is a warranty. But I know many guys who never checked their diff levels or AT fluid levels until they wanted to drain and refill. Typically that might be more than 50,000 miles for a diff and 100,000 miles or AT. When I got my 2016, because it was a “thing” when the Gen 3 was introduced, I did have dealer agree to check my AT fluid at purchase. I witnessed it. My AT fluid was fine. And my dealer admitted they had already replaced an automatic transmission because a customer’s TRDOR (with tow package) was under-filled at the factory. The AT was slipping and performing abnormally and this customer was putting many miles on quickly. Realizing the AT could have been under filled, I decided to check the rear diff, transfer case and front diff levels. The rear diff and transfer case were oozing fluid full to bottom of fill hole. That was great! My front diff was 0.6 quarts low and it only holds 1.5 quarts. The front diff being that low is unacceptable. So I have first hand knowledge that human errors at factory have resulted in low AT fluids (resulting in replacement of AT) and front diff fluid level (mine) being 40% low. I want my Tacoma to outlast the warranty. That is not possible without these fluid levels being correct. 6 months out of a year, my TRDOR is in 4WD Lo (several times each week) at my farm and hunting trips. When I get my 2023 home I’ll check all these myself and I expect them to be full enough to prevent damage or pre-mature wear, if I had not checked them for 50,000 miles. If they are low I’ll fill them properly.

 

The dealer saying it was impossible is uninformed. It’s just a pain in the butt.

 

Maybe it was just the rep I was assigned. Either way, I really don’t want to do it myself.

 

I understand. It should not be necessary. But if you want your truck to outlast the warranty, you need to check them all.

 

My diffs are fine. Tcase could be checked. That’s easier, from my understanding.

 

Trans fluid check link


https://www.tacomaworld.com/threads/3rd-gen-automatic-transmission-fluid-level-check-diy.547455/