Differential Breather Extending

Huh?

You know when you're sitting at a light and underneath the car/truck/van in front of you, you see that circular thing in the middle? That's the differential. To those of you not in the know, your differentials have to breath. It's good that they breath. They get cold and they can suck air in. They got hot and they can let air out. If they didn't have a breather, they would blow the oil inside past seals and eventually leak... That would be bad.

The normal differential breather on most vehicles is up to this task. But what happens when you go off-road and cross a stream; your differential, while underwater, needs to breath to compensate for the contraction that all things experience when they get cold? Guys you know what I'm talking about... Well, it's underwater, it's not going to breath air and that's bad. Inside the differential is oil and oil and water don't mix well, do they? What to do? What to do?

How To Extend Your Tundra's Rear Differential

1. Go to you local Toyota dealership and purchase part# 90404-51319 Union

If you're lucky you'll have someone like Ricardo here who'll give you a discount in exchange for taking a picture of him for your blog! If you're unlucky, you'll get the guy in the back.

2. Go pickup about 15' of 3/8" fuel/air line. You probably won't need quite that much but extra is always better than not enough.

3. While you're getting the fuel/air line, pick up a bunch of HEAVY DUTY zip ties.

4. Park your truck in the driveway set the emergency brake, chock the tire (safety first! you'll be under that thing!).

5. Run inside to your PC, open your browser go to this blog, print this article and take back outside for reference.

OK, on to the real meat of the thing...

6. You'll need some tools to do this job.

At a minimum you'll need: 12mm and 14mm wrenches, CR-VT-30 torx (I really don't know what that means, but it's the thing that lets you remove the tail light housing, just look at it and find the one that fits), scissors to cut tubing, the aforementioned zip ties, and being an old punk-rocker/skater I enlisted the help of my old friend... duct tape. Man, I love that stuff! Got all your stuff? Let's continue.

7. Open up your truck tailgate, and look on the now exposed vertical plane to your left.

Ok, you see the two torx bolts? I know there's four, but we're not going to mess with the two holding the metal latch for the tailgate, ok? You want to take out the top and bottom ones. Once you do that...

8. You should be able to gently slide the tail light assembly out and let it hang down.

Inside, you'll see the strut that makes lowering and raising the tailgate that much easier, you lucky Tundra owner you. I chose to extend my differential to this point mostly because of other articles by much better people than myself. Now to the underworld...

9. Grab your 14mm and 12mm wrenches, your newly purchased union, your zip ties, your print out of this blog, and if you're an old punk rocker/skater your duct tape, and climb under the back of the truck.

10. The doohickey you're looking for will be on top of the differential about eight inches off-center favoring the driver's side. Take you 14mm wrench and remove this. If you're lucky, you won't hear, ppppssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss, as you remove it, like I did. If you do, this means your breather wasn't working and your differential had built up pressure. Good thing you're doing this mod, huh? 

11. After you remove the old breather, take your newly purchase union, your 12mm wrench and install the union. Careful to not cross-thread!!! After you're done it should resemble this:

12. Okay the rest from here is highly up to your interpretation of what works best. I'll show some pics of how I routed mine, but get creative and make this your own routing of the 3/8" line up to the tailgate strut area. 1st Hint: poke the hose through the tail light area down, feeding roughly enough to route to the differential. This is easier than going from bottom-up. 2nd Hint: If you are going to install a lift later, leave enough slack to compensate for the amount of lift desired.

As you can see, this is where the zip ties come in handy. Let's move out to the tail light area where you have routed your hose. 

12. After the lengthy 11., you'll find yourself back in the sunlight, staring at the tailgate strut and all the excess hose leftover. What I did at this point, was route the tubing up the side and over the top of the strut, secure it with zip ties and duct tape (that stuff ROCKS!!!), install a breather on the end (not pictured)...

13. Take your torx thingie and put your tail light housing back on and you're ready to fearlessly cross streams, rivers, lakes or, if you live in Houston, our streets after a heavy rain, without the fear of contaminating the oil in your rear differential. Thanks for reading.

HEY!!! WAIT!!! I have a 4WD Tundra! What about the front differential? THIS IS NOT CONFIRMED: I talked to several Toyota technicians and I was told that the transmission, transfer case and front differential were ALL extended into the engine bay by the front strut/motor-mount area on the passenger's side. If this is the case great, I couldn't find it. I have looked at some exploded parts diagrams for the 2010 4.6l Tundra's drive train, and it does show unions and breather hoses for these parts. I did not look for the 5.7l so you guys will have to do some digging on your own.

Good luck and good night.