Whoops, ran my truck a little low on dif oil...

So yesterday I decided I was going to change my rear differential oil on my 09 Tacoma 2wd and I read that I need 3 quarts of oil to fill it up. So I go and buy exactly 3 quarts of 75-90 synthetic oil thinking this is really going to be treating my vehicle good. I drive an hour out to my brothers house in the middle of nowhere because he has all the tools necessary to do the job and the know how to help me.

We empty it all out (and it was perfectly clean and clear and looked brand new after 210k km on the truck??) and then we start adding. The truck is on a slight incline (maybe 5 degrees) with the back wheels a bit higher. We of course spill some trying to get it all in there and then when it comes to the last drop, of course it isn't level with the hole and seeping out. He sticks a piece of metal in and sees that its just below the hole maybe a quarter inch? Not far at all. He says that because the truck is on an incline it would probably pour out anyways and he reckons it's just fine how it is.

I agree with him reluctantly seeing how I don't have a choice and drive off into the sunset. I read the whole way home that you need to fill up the dif then drive a little bit to coat everything then fill it up again. Reading that its splash lubricated and too much isn't an issue and too little is definitely an issue. I drive very gingerly but at the speed limit the entire 90km or so home, listening for any whining or issues and all sounds great to me.

It bugs me the whole next day so I go and buy another litre of oil and decide to add. I ADDED ANOTHER 450ML OF OIL BEFORE IT STARTED SEEPING OUT *facepalm*.

What I'd like to ask is how big of a deal is this and if I heard no noises is there any damage I could've done to my differential in this time period of driving 90km? Is 450ml of oil a large amount short for a differential? Would everything still have been lubricated anyways just not optimally?

Educate me please.

 

No everything is fine.

 

definitely not a big deal... you could probably drive for another 200000km without the 450ml in there and it'd still be fine.. dont worry about it lol

 

450ml is just under half a quart. You still had 2 1/2 in there. Should be fine

 

Be interesting to hear input from mechanic types. I'd think you might be okay. But, being low on lube back there is certainly not good.

I'm pretty paranoid with my diff because it's been replaced 3 times (truck has 34k miles). That's what happens when you change gears and someone doesn't set them up right though.

If you're concerned you could drive it a couple thousand miles and then spill the fluid again and see if you get any metals in it. If not fill it back up (properly) and go on with life.

 

That is entirely not necessary, if you had run it dry that's cause for concern, but running 2.5 qts for 1 day when there should have been 3 is absolutely not an issue.

 

The ring gear goes almost to the bottom of the housing and slings gear oil everywhere. Everything is just fine.

 

Well, you guys all made me feel a little silly and a lot better. Thank you haha. For those of you who are still reading this thread, why is it that dif oil that was still stock from the factory at 210000km still be perfectly clear clean and look brand new as far as I can tell? How often do I actually need to replace this stuff?

 

The diff doesn't get hot like the engine, so you won't get the dark coloring you get with engine oil. It might look fine, but at that mileage it was due for a change.

 

Temperatures in the Tacoma rear diff can reach well over 225F if you are towing. If you run low on lube, the first thing to go will be pinion bearing, located in the nose of the diff. If you have any concerns, check that for play.

 

https://youtu.be/XH_w20UYbg0

 

OP you are fine. keep on driving