Water intrusion from washing undercarriage?

I went off-roading in my 2022 4Runner and went through some pretty deep mud. When I got home I laid underneath my truck with a garden hose and went to town washing all the mud off. I was focusing on the axles, differentials, suspension and transfer case/transmission area. It didn’t occur to me until later that the transmission, transfer case and differentials all have breathers that I imagine were directly hit with water from the garden hose at full blast.

Do you think there is any concern of water intruding into the transfer case, transmission or differentials through the breathers if they were hit with full water pressure from a garden hose? Wondering if I should check the drain plugs for water or if it’s something I should just continue driving until the next fluid service interval. I’m at 13k miles now and was planning to do the differentials at 15k and the transmission at 30k.

 

If water intrusion occurred from a simple garden hose think about what happened when you went mudding? Or when it rains? Or when you drive thru a car wash (they spray the undercarriage with high pressure sprayers.

The point I'm getting at is, you should be fine.

 

Thanks for the reassurance! I was a little worried because I wasn’t sure how the breathers work, whether they were one way valves or open. I’m pretty sure I hit them directly from the side with the jet setting on my garden hose so was a little paranoid that I may have gotten water in the TC/diffs,transmission but I’ve driven about 100 miles since and haven’t noticed any issues.

If there little risk of getting water in from the breathers then I’ll just wait until the next fluid service interval to check.

 

The rear differential has a check valve on top of it. The others' breathers are extended into the engine bay. All that to say, the rear diff is the most vulnerable to water intrusion. If you're really concerned, you could get the rear differential's fluid changed.

 

Yup. And depending on how deep you sunk it and how watery the mud was, it wouldn’t be a bad idea to change the rear diff oil regardless.

 

I didn’t sink up to where the diff breather was. Was mostly concerned with if I could have introduced water to the diff if I hit the breather directly with the hose.

I decided to just order some diff fluid and change the rear diff anyway to be safe. If there is water then I’ll do the rest of the fluids as well.

If I do have some water in the diff fluid, how much damage could it do? I’ve driven about 200 miles since hosing down the undercarriage so just curious if some water in the diff fluid could do any long term damage with a couple hundred miles driven like that.

 

I'd be more worried about the deep mud over the hose.

 

The breather is a raised nozzle with a swaged cap over it. A stream of water from the outside can't enter the breather. Only way for water to get in is by complete submersion.