Can you overfill differentials

My truck is 2012 Tacoma off road. I'm changing my front differential first and drained out 41 ounces. The manual calls for 1.59 quarts which is 50.88 ounces. I put in 51-52 ounces but no oil came out the fill hole. I feel that I have enough but should I add it till it comes out, and us it possible I lost or burned off 10 ounces of oil?

 

Hard to overfill as the excess drains off after you pull the fill hose/funnel/whatever and have reached around for the top plug to reinstall.

 

Fill until it weeps out the check hole.

 

Is your truck on a level surface?? As long as you're using the proper 'fill hole' and you stop filling when it starts to come out of the fill hole...you should be good.

Yes...you can overfill a differential. Too much oil creates an excessive amount of heat /pressure that can't vent properly. You can blow out seals and cause leaks.

 

Alright the rear weeped out the check hole as well as the transfer case. The only one that didn't was the front diff but it's got to be close. I'm assuming I was in worse shape before when it was low. It hasn't had black oil and more metal stuck on the magnet than the rear.

 

Interesting topic.

Just did the rear diff and ended up filling over 3.5 qts, though the spec is 3.1 so i prob have 8 oz over spec.

On another note, it must have been low from the factory, as i only drained 2.5

 

My last year 1st Gen Tacoma(2004) came from the factory low on differential fluid.

 

Typically, the excessive heat/pressure problem is caused by introducing water or dirt into the differential, or having a fancy (but obsolete) limited slip. In fact, you CANNOT overfill a conventional open differential. You could fill it up all the way to the top and it would be just fine. Maybe a little bit more drag, but fine.

Consider things like marine gear cases. They are full of the same kind of oil, bottom to top (no air), and *sealed*. They are also subject to far greater stress since marine engines typically operate a lot closer (or at) their peak for extended periods. The gears are also smaller, and turn faster. And while you might be right about the water surrounding them being more conductive than an automotive differential case, the surface area is FAR smaller. Yes, marine gear cases get *HOT*.

 

Revive
If I torqued my diff already with new washers is it bad that I open it back up to see if I’m low or overfilled?

 

Should not be a problem.

I have sinned in the eyes of the most anal and reused crush washers multiple times and never had a leak. Oil pans, transmissions, differentials.

 

What a coincidence...I just did my front/rear diff & transfer case yesterday also

1.6 in the front, 1.1 for tcase, & 3.2 in the rear
Can't wait to drive my taco & enjoy the fresh fluids

 

if you fill it on a incline like my dumb ass did you can lmao.

 

2015 thread

 

I am in this post and I do not like it.

-J





















I have done this many times too. I always check the condition of the washer before reuse though, especially if it looks janky. Just make sure it's torqued to spec.