Overfilling rear differential with 5 Qts?

I just changed the rear differential fluid in a 2019 Tacoma TRD 4X4 Sport (Manual Transmission) and was surprised to see that it apparently took an extra quart (exactly 5 total) to bring it up to the fill plug level. I was on completely level ground, too. It was just trickling out when I re-installed the fill plug after the fifth quart. I re-filled the old bottles to recycle and found I could only fill four bottles (four quarts) with the old fluid. The manual said it would only take 4 quarts.

Question: Did I just overfill my rear differential or was it one quart low?

I kinda think having the larger rear diff (like the OR models) minus the volume of the locking mechanism could account for the additional capacity for fluid.

 

totally the truth !

many dont have enuf
wears out the outer axle bearings prematurely

when low going around corner.......the slosh runs towards the axle bearing
yet goin straight they might have little

will wear the pinion bearing long term
as not enuf in the sump to ' REconstitute ' the oil under heavy use/load
more the concern when trailering or other heavy load scenarios

the diff is vented
will blow out excess oil.........seldom happens at all

 

If you drained it and filled to the fill plug hole, then it doesn't matter how much came out or went in. It takes what it takes to get to the hole, unless its leaking out somewhere.

 

Unless the axle seals or pinion seal are leaking there's nowhere for it to go so it probably was under filled. But I get where you're coming from, my OCD likes when it's supposed to be 4 quarts and that's how much comes out and goes back in. But in this case filled to the hole on level ground is the most important part, so you should be fine.

 

3rd gen rear ends hold a whole 2 extra quarts compared to the 2nd gens..?

 

I seem to remember my rear end taking more fluid than I expected. I didn't measure how much came out though.

 

All MT have the 8.75in diff.

 

Mine took 4.5qts just like this thread noted:
https://www.tacomaworld.com/threads...-manual-transmission-6mt-fluid-change.481719/

 

FYI. There are many wannabe engineers on TW indicating you should do this, stop that or use a certain brand of anything. Proceed with caution.

Should we also add two additional quarts of engine oil or an extra half a can of freon? This is the more must be better mentality.

 

Toyota's procedure for filling axles has always been some variation of this.




But later warns.



Which for his truck yields a discrepancy.



So what do you recommend he do? Is the number of quarts correct or is the actual measurement correct? Being a quart low in the axle isn't immediately damaging but will cause bearings to wear, with the greatest risk being starving the pinion bearing.

I've always used the fill until gear lube trickles out on level ground procedure but I've also been lucky perhaps that the amount going in is within half a quart of what I expect.

Something I do wonder is whether the truck is stock or modified. If the axle is rotated that affects levels.

 

Page 2142 of the 3rd gen Tacoma maintenance manual states
"Check that the oil level is within 5 mm (0 to 0.20 in.) of the
bottom of the filler plug opening."

 

Thats kind of what Im curious about.. On the 2nd Gens (well my truck at least) both methods agree. Takes just about 3 qts from empty to reach the bottom of the fill plug. The manual calls out 3.12 qts.

Not saying "overfilling" as is the case with OP is going to cause problems, but Toyota engineers are pretty smart

 

Which engineer do you listen to? The one stating the level or the one stating the volume?

 

Jesus guys its gear oil. Don't overthink it

 

Clearly the volume, cause that makes me right

But nahh its a good point. I was only looking at the OM

 

It's Friday

 

It's curious why the two don't match but it wouldn't be the first thing Toyota has screwed up. Do they still call for 37 ft-lb on leaf spring u-bolts?

 

So many misconceptions. Everyone please watch this before further comments:

https://m.youtube.com/watch?v=9-yG3D3JBRs

 

That entire series was interesting. Even more to criticize every time I see a little-D truck douche with his flatback cover and 20" drop drawbar...