vacuum hose

Hi, Where does the vacuum line go on the tc accuator? Just a vent, or some other purpose? Thanks

 

The little vacuum hose on the transfer case actuator is just a vent line. It goes from the actuator to a nipple on the transfer case itself.

Theres actually a vent line on all the actuators (front diff, tcase, rear locker - if equipped).

 

TC line goes up into the drivers side of the engine compartment and ends in a dual clip with that being the smaller hose and metal vent end and the other larger one next to it the front diff vent.

 

Got it - Thanks

 

Nope.

Two vent lines on the inner fender by the fuse box are, Big = front diff breather, small = front diff actuator.

Transfer case actuator vent line like stated, vents into the case of the transfer case. The transfer case has one breather tube that runs along the top of the transmission and ends at the base of the bell housing.

The transmission (auto or manual) has a vent line that runs along the top of the transmission up the bell housing about 3/4 the way up

 

nd4spdbh thanks for straightening this out.
I just changed the front diff breather after the ECGS bushing, seals and new CVs but never looked back up there as pretty tight.
I seem to recall someone did post a pic of the top of the trans and firewall area showing those hoses up in there once.
Thanks - correct info is the reason for this forum.

 

Read many post about the rubber line on the transfer case actuator drying out/ cracking etc and letting in water. And mentioning that this is one of the main causes of failure.
is it just regular vacuum hose? What size is it internally? ? Should it be replaced at say every 5/10 years? Since the actuator is quite pricey that seems like a good preventative and cheap maintenance item. Maybe replaced with some high temp silicone version for a permanent fix?

 

Yeah, pretty much your standard vacuum line. The transfer case actuator hose is more prone to cracking in part because of the angle that the hose is bent at (it makes a 180 in a relatively short radius). My 10-yr old Taco was very close to having it fall off the nipple due to the cracking.

What I found was that cutting off about 3/4 of an inch of the hose and using a right angle connector and a short length of vacuum line allowed me to completely fix the problem and relieve the strain on the connections. The rest of the hose looked very good.

By comparison, the hose on the front actuator that doesn’t have that bend looked just fine.

 

Where did you find a 90 degree fitting. Looked on Amazon and found lots of straight and T fittings but no plain 90 degree elbows.
If Toyota has made it so this fitting was positioned downward it would have probably eliminated this problem all together.
Being metric I believe the standard vacuum line is most likely 3 or 4mm (1/8 or 5/32) internal diameter but will measure to confirm

 

I bought mine locally at Napa Auto Parts, it was a male to male elbow but it looks like there are also soft female to male types available as well.

https://www.napaonline.com/en/search?text=vacuum elbow
https://www.autozone.com/fittings-a...ubing-connector-assortment-6-piece/426015_0_0
https://www.autozone.com/fittings-a...ubing-connector-assortment-4-piece/426018_0_0

Hope that helps!

 

Exactly what I needed. Thanks. Its Dorman Part # 47355 for anyone that also looking.

Now I just need to find some place that has it at a reasonable price. It shows as $7 US and is over $20 on Amazon Canada. Will see if its in stock at my local CDN tire.

I just crawled under and the tubing still looks good. But as soon as I can assemble the required parts I will make the repair in advance so I don't have to worry about it in the future.

I can see it goes up onto the top of the transfer case but from underneath I can't really see where it connects. If I had it on a hoist I could probably see it that way but as mentioned here it just connects to the transfer case breather connection on top.

 

How many of those that have experienced failure of the 4wd actuator have been thru water deep enough to reach the vent tube?
With the larger fluid filled components like the front and rear diff and transmission we all know that as they heat up and cool down they can indeed experience both positive and negative air pressure and need a vent to counteract this. The actuator is so small and only air filled i am thinking it experiences minimal changes in pressure (but not zero)

But if the truck is warm, the vent hose if cracked and/or separated and you happen to cross water deep enough to reach the vent nipple that the cooling effect of the water would induce a minuscule but non zero negative pressure in the actuator and allow water to be sucked in?

Another thought is that since this hose going to this vent is at the bottom of a long series of tubes that vent the transfer case and transmission that any moisture in that series of tubes can condense and migrate down to the actuator? And unlike the other components it would never get warm enough to boil off that moisture?

What about just giving the actuator its own vent tube and routing this up into the engine compartment with its own two way valve like all the others?

 

In my reading of reported actuator issues on TW over the last year, it isn’t just water crossings, but splashing of water into that open vent tube. Once the hose falls off, of course. It seems improbable as it’s such a small opening, but looks like it does happen.

As long as the hose is in good condition and is properly connected, I don’t think many people are experiencing water-induced corrosion in the actuator; the breather valve is in a fairly high location. It’s the rear differential breather that’ll see some water first due to river crossings and such.

 

For those that are interested the diameter of the vent tube on the actuator is 0.225 inches (the plastic nipple, not the rubber hose)
Was under checking its condition and figured it was worthwhile knowing how big it was if I went looking for replacement tubing.
Its basically just a hair larger than a 7/32 drill bit which I measured for comparison.

 

If you are looking for a good replacement for that vent tube I purchased some thin wall silicone vacuum tubing
Internal diameter 4mm
Wall thickness 1 mm

It fits very snugly on a 7/32 inch drill bit (0.212 diameter) and thus would also fit just as snugly on the vent tube nipple (0.225 diameter) . I even added a 7 mm ID spring band clamp for overkill since I had one and wanted to see if it would fit. The band clamp isn't really needed since its just a vent tube and the tubing fits even more snugly than the original rubber one. This is what it looks like as a test fit on the 7/32 drill bit. Being thin wall its extremely flexible and silicone would never suffer the fate of the rubber tubing.

This is the tubing if you wish to obtain some

$9 uxcell Silicone Tube, 5/32"(4mm) ID x 1/4"(6mm) OD 10ft Silicone Rubber Tube Air Hose Water Pipe for Pump Transfer Black

https://www.amazon.ca/gp/product/B08L335C7Y?ie=UTF8

 

Has anyone seen similar degradation of the vent tube on the front differential disconnector? If so think I may use the same application there as well...