When do we need to do the diff-breather mod?

[BrianSD_42]

I recently went on a trip with some minor water passes.

We were in Big Bear Lake, CA. It was about 50F outside and the trails were mud and snow. I drove through some small water crossings, probably about 10-15" of icy water.

I havent done the diff-breather mod, is there a chance i got water in my diff or is that only in very severe water crossings?

I can either do nothing, do the mod or drain fluids + mod to be safe.

Please only answer if you KNOW for sure when this mod is required, what water levels ect.

Thanks.

 

[brian2sun]

Anytime the water level is higher than the stock breather on top of your diff, you risk getting water in it. If you stop while crossing, you stand a much bigger chance because as long as the diff is turning it has a little more pressure inside and that helps keep water out too. 10-15" isn't probably enough to worry about. I crossed water (up to about 2') many times before I did the breather mod and I never got water in mine.

If you are worried about it, you could always drain a little out and check it. I would just have a quart on hand to fill it back up in case you loose a little too much.

 

[Mellow77]

Being in SD you probably don't have to worry about corrosion as much as other areas but my diff breather was actually corroded shut. In my case it led to blowing the rear axle seals because that was the next available place for pressure to be relieved. Any corrosion around the valve could cause it to stick open as well so a quick check to make sure it's functioning correctly would be good.

I agree with Brian; I really doubt you have anything to worry about. I have also had my rig in 2'+ of water and didn't have a problem. I did not stop while in the water and only had the axle submerged for 10-15 seconds at a time (multiple runs while practicing bow waves). I changed the diff fluid soon after and saw no signs of water in the fluid.

A quick check and then do the mod before your next trip out. It's pretty easy.

 

[BrianSD_42]

ok i can check it by doing a small drain. if there is water it should come out first since the oil floats higher.

 

[sportscarfan]

I'd do it anyway, and did back in Nov. before a 500 mile drive to the desert. If it's original, chances are good it doesn't work like it should. With the spare out of the way it's easy. I routed to behind the fuel door.

 

[Kurtis]

When you hit a cold puddle of water when your axle is at operating temperature it can suck in water because of the cooling action of the cold water. Doing the diff breather mod or another option is always a safe bet.

 

[Big John]

Kurtis is correct.

You can probably get away with pulling the fill plug and sticking your finger in and see if there's anything funky floating on top.

Any time you stick your finger in a hole and come out with slimy, milky looking stuff, it's time to drain your fluids or get to a doctor.:lol:

 

[HCurphy]

ok i can check it by doing a small drain. if there is water it should come out first since the oil floats higher.

I would think the oil would be more dense, thus water would float on it. Not positive, but a simple experiment could be performed to check.

Also, I'm far from an expert but as long as your breather is functioning you shouldn't need the mod or to change your gear oil. That raises the question of is it functioning though, I guess.

I say **** it and do the mod, but I highly doubt you got water intrusion so you probably don't need the new fluid--unless it's time anyway.

 

[redyotarunner]

Like the others have said you shouldn't have water in your diff from that little water but you can check by removing the fill plug and sticking you finger in to see the condition and level of your fluid. If you don't plan on crossing water that's any deeper that 10-15" then you will not need the mod but any deeper then 20" or so you would be safer to do the mod.

 

[fightman80]

I procrastinated for ever to do the Diff Breather mod....wish I wouldn't have...might have saved myself a rear axle seal job!

Here's a link to my write-up....pretty easy project...costs less than $20.00 to do...and less than 20 minutes of your time.

http://www.toyota-4runner.org/3rd-gen-t4rs/65845-fightmans-build-thread-4.html

 

[BrianSD_42]

See attached

 

[HCurphy]

^^^well there you go. I was mistaken.

 

[MTDewX8]

I was going to answer, but pics top all for sure.

Oil is lighter.

also I know water is heavier than aviation fuel. that is why the sumps are on the bottom of the tank.

I have all the parts but the hose to do the job. just have to get around to it

 

[tattooedblade]

anytime you submerse the diff you should change the fluid always the safest bet. Do the breather mode, change he fluid and then you have peace of mind and don't have to worry about it next time. Diff fluid is not the expensive anyways. easy DIY project or most shops run deals on changing diff fluid.

 

[BrianSD_42]

what about the front diff?

 

[quicksilvr]

what about the front diff?

It has an extended breather from the factory. Look down past the drivers side of the intake manifold, and you'll see it clipped onto the inside of the wheel well.

Really, changing both diffs and the t-case is not very time consuming, and the fluid isn't THAT expensive even for good stuff. I'd just do it. A good hand pump makes a difference. I tried using a crappy one once....and it made me say bad words.

 

[Kurtis]

Another option here:

http://www.toyota-4runner.org/3rd-gen-t4rs/104397-why-does-everyone-extend-their-diff-breather-instead.html