Do I need to replace my Differential fluid?

I spent to better part of Sunday on the trails in Ocala National Forest. Quite a bit of water, some up and over the wheels. I don’t have a breather yet so do I need to drain and replace the diff fluid. Transmission too? If it makes a difference it was the first time I had water crossings.

 

Most likely, you are fine. Vent valve can take on some light water crossings. It does prevent water from getting in while letting the diff breathe.

But if you want to be sure, there is really no other way than to drain and fill.

 

You could open up the fill plug and see if there is any water. It'd be a milky color if water got in. How many miles are on it?

I just changed my diff fluid at 15k and aside from the metal shavings on the magnet the fluid was pretty clear for 15k but was wanting to get all that old stuff out anyway. And I hadn't done the breather mod at the time I did water crossings so I was on the "what if" side.

It's super easy to change compared to other vehicles

 

Yeah super easy. My front diff oil was real dark when I changed it at 15K and I don't wheel all that often.

Use synthetic to replace.

While yer down there checking fluid, its only one more plug. Just plan on changing it out and save you the trouble crawling around 3x.

Be sure to remove the fill plug 1st. very important. 1st time I changed mine the drain plug I needed to use a breaker bar to get it open on 1 of em. Need a few crush washers and some special washers if you're doing all of it. There's a kit on azon.

$14 GENUINE TOYOTA GASKET KIT FOR TRANSFER AND DIFFERENTIAL SERVICE

https://www.amazon.com/gp/product/B017V4BAXI/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

crush washers needed too handy to have extras.

$22 Toyota Oil Drain Plug Crushable Steel Gaskets Set of 10 OEM 12157-10010

https://www.amazon.com/gp/product/B01FUVMDBC/ref=oh_aui_detailpage_o00_s03?ie=UTF8&psc=1

I just ordered 2 sets of the diff/transfer and a 10 pack of the crush washers.

Not sure about the diff/transfer kit - there's not enough crush washers there so you need some extra but the copper and flat washers you need them. Some folks probably dont replace them. Couple of bucks and no worries. done

 

Remember, dif breather 1st, then try it out in the water.

But do the oil test first - water will be at the bottom of the diff if you let it sit for a day.

 

if you have over 5k miles on the original oil change it regardless.... that break in oil is gonna look nasty and have all sorts of metal shavings in it.

Also its not the OEM breather that will let in water (as its a one way valve that only lets pressure out) its the fact that it does only let pressure out which means a vacuum can get created easily when you dunk a hot axle in cold water and water will get sucked in the pinion and axle seals rather easily.

 

i changed mine at 25k with very little debris on the magnet. using amsoil

$30 75w 90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w 90 gl5.

 

First oil change at 1k and diffs and transfer case at 10k for me

 

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