Whats the point behing the vacuum activated TC

[peteinjp]

Having just gotten a hold of my bj44 I did what any decent (and curious) owner would do and headed down to the nearest spot that would require 4wd to check it out. Well just to be sure everything was kosher before getting my a** stuck I pulled the FD knob out while still on the dirt road- hubs locked of course. Well- no front engagement.

Feeling rather disappointed I headed back home to figure out what the issue is. Verified the hubs are locked then did a visual on the vacuum system. There is a vacuum hose with some cracking in it- it may be the problem. But I got to wondering- why all this extra stuff just to engage the front wheels. What is the reasoning.

Personally I'd much prefer to have the TC engage the front axle with a shift lever- and I have searched and found that this seems possible to accomplish. So I'm leaning toward this modification- unless there is some good reason to keep the vacuum system. frankly I can't imagine what it would be....

FWIW this is an 81 model with a 4 speed.

Best!

Pete

 

[Dieseler]

Changing the hose would be the esiest.s and quickest than fabbing up the twin stick unless you have the tools and ability to modify, I also wonder why they use the vacume system I guess Toyota wanted to keep it simple for tha average driver rather than confussing them with two shift levers.

 

[peteinjp]

But.... all the other 4wd cars I've driven have a single lever- 2h, 4h and 4l (wit a neutral in there some where).... this is even simpler than having a lever and a knob... Even other cruiser TC's have such an arrangement- no?


P

 

[Devilmans Hand]

I wouldn't mind having it vacuum activated. This would help prevent your passenger from accidentally knocking the transfer case shifter out of 4lo/2lo, especially when you're going down a steep hill over rocks.

 

[peteinjp]

I can see that- but based on this one experience the possibility that there will be mechanical failure seems more likely to be a problem. Aside from the tubing to the TC itself there is also the solenoid that can fail as well as the (specific to diesel?) possibility of tubing failing to the mystery tank that sits under the left side seat. It just seems more fool proof over all to have a single lever..... I still don't get it...

I guess the thing is that I was really hoping to get out and drive tomorrow but now I can't- and this would never happen if it weren't for the use of a more complicated system. I have to replace the hose just to find out if that is indeed the problem.


P

 

[crushr]

The reason for the vaccum shift and the 3 on the tree in the early cruisers was to eliminate all shift levers from the floor so to allow 3 people to sit across comfortably on the early bench seat. Toyota published numerous early print adds for the FJ40 stating as a significant selling point: "carries 7 adults in complete comfort" or something similar, claiming that you could have 3 adults on the front bench seat and 2 adults on each jump seat.

Although it is somewhat mechanically complex, the general experience with the FJ40 vacuum shift setup seems to be that it is extremely reliable. It is also considerably quiter than a floor shift setup, as the floor shifter will allow more gear whine and road noise through the shifter opening.

That said, it is fairly easy to convert a vacuum shift xfer case to direct shift with the appropriate shifter/linkage and xfer case nose cone actuator parts. D'animal had a setup for sale at one time in his "virtual garage sale" thread, don't know if its still available:
https://forum.ih8mud.com/sale-parts/285745-land-cruiser-parts-virtual-garage-sale-central-ca-5.html
see post #98

PS: Just noticed you have an 81 BJ44 which means at least some of the above does not apply to you, particularly I assume that D'animals conversion setup would not work on your truck, due to xfer case differences.

 

[Dieseler]

But.... all the other 4wd cars I've driven have a single lever- 2h, 4h and 4l (wit a neutral in there some where).... this is even simpler than having a lever and a knob... Even other cruiser TC's have such an arrangement- no?


P

Thats the pattern found on the BJ42 with the 5 spd I dont think it was used on the 4spd

 

[Brian in Oregon]

The reason for the vaccum shift and the 3 on the tree in the early cruisers was to eliminate all shift levers from the floor so to allow 3 people to sit across comfortably on the early bench seat. Toyota published numerous early print adds for the FJ40 stating as a significant selling point: "carries 7 adults in complete comfort" or something similar, claiming that you could have 3 adults on the front bench seat and 2 adults on each jump seat.

Well, I've transported six teenagers in my '71 FJ40, though it has a '79 transmission and transfer case with floor shift, which makes it ungainly to say the least for the middle front seat passenger. I can't see transporting six Hoss Cartwrights in it, though. But driving around with seven people sure makes Heep owners turn their heads.

 

[peteinjp]

Well no bench seat in this ride- so no n*t bustin here. The other thing is that the vacuum runs off of the vac pump on the alt. Are the gas models set up like this also or do they run off the manifold vacuum? I guess what gets me concerned about the system is 1- I'm in Japan. Its not like I can just make a phone call and have a part in a day or 2- not even a vacuum hose. And secondly its a 24v system and I'm new to the cruiser game. I'm not so sure I can find the solenoid even if I wanted to. For now I'll definitely just order some new hoses (no such thing at an autoparts store here) and see if that is indeed the issue. at least one of the double solenoids is working fine as I can hear is click open. The vacuum is fine because the power brakes are working and they also run off the same pump.

In the long run I'll go for something mechanical- either with a 5 speed or addition bits on the 4. I'm hoping to own this thing for a long long time. Anything with a diaphragm will go eventually and likely be hard to replace in another 20 years.

I use 4wd daily in the winter and without it there's a good chance I can't even get out of the driveway.....

Thanks-

Pete

 

[lc69hunter]

My 69 ran off manifold vacuum. When adjusted properly, it works great, and much quieter than the floor shifter. also, as mentioned before, it takes up far less room in the cab.

When I first bought mine, and did the same as you, took it out and tested it, the 4wd indicator light on the dash lit up, but no engagement. That light is activated at the transfer case, indicating the vacuum system was working. I pulled the cover on the transfer case and lo and behold, the fork was twisted. It was an easy fix.

 

[albee]

I have never had a problem with any of the vac shifters that I have had. I like being able to use 2low, 4low and 4high.
You can take the cover off where the hoses connect to the t-case and shift by hand if you need to.
Good luck Al

 

[Living in the Past]

I'm curious what the vacuum shift looks like on your BJ44. On the earlier one piece case it a simple switch. But on the FJ62 the vacuum is different than manual shift. The main housing is different in the nose cone area. So is this the same as the FJ62 or did Toyota make a vacumm shift that just bolts on. I'm guessing they did make one.

 

[Dieseler]

Hey peteinjp did you try shifting it into L4 , I have found with some of the JDMs I have brought over needed some patience to get them functioning.
I think a few of these have never been put into 4W ever so it took awhile to get them to engage by shifting up and down on the transfer shifter and pulling the FW knob on the dash in and out a few times last time I used 4w on my 44 it took a kilometer on gravel for it to dissengage.
From what I can see the solenoid looks similar to the one in my HJ61 and FJ62

 

[middlecalf]

With the vacuum shifter you can also shift on the fly (2H into 4H) without stopping or reaching down. I find this handy when traversing from nominal dirt roads to not-so-nominal dirt roads/fields/pastures, or on washboarded roads to help keep the back end from skidding out with the help of the pull from the front end. I have an electric "version" of this in my '04 GMC Sierra, has saved my butt several times with black ice. I guess the vacuum shifter is a first generation version of the modern electric transfer case shifters, dunno. Of course, the hubs need to be spun in, so in either case your not saving wear-n-tear on the front axle+.

 

[Dieseler]

You can shift on the fly with the manual shift as in the 5 spd set up,I have never tried on the fly with the vacume version.
I do know if you pull out the switch without the hubs locked it makes an ugly grinding noise the BJ41s have the switch beside the wiper switch and driving along in the dark I have accidently pulled the wrong one...Ouch.

 

[peteinjp]

Thanks again guys- Dieseler- I did try 4L several times. There is a slightly cracked hose going to the TC- hopefully that is the only problem. I did contact the PO just out of curiosity. I told me that he used it in 4wd recently. Just shift to 4L and you can the "4wd sound." He's talking about the low gear whine. He didn't mention anything about the vacuum switch. I had a good chuckle. It seems he didn't know about engaging the front axle- I guess for some 4wd is more of a state of mind.

So you may be right Dieseler- I would not be surprised if this truck had only been in 4wd once or twice in its life.

 

[The911s]

Thanks again guys- Dieseler- I did try 4L several times. There is a slightly cracked hose going to the TC- hopefully that is the only problem. I did contact the PO just out of curiosity. I told me that he used it in 4wd recently. Just shift to 4L and you can the "4wd sound." He's talking about the low gear whine. He didn't mention anything about the vacuum switch. I had a good chuckle. It seems he didn't know about engaging the front axle- I guess for some 4wd is more of a state of mind.

So you may be right Dieseler- I would not be surprised if this truck had only been in 4wd once or twice in its life.

Pete - I've also wondered why they used a vacuum setup. No idea...

I think your issue with 4WD not engaging is common. On my cruiser it hadn't been used in a while and I got under there and just manually jiggered the fork back and forth a few times and it came free. Sometimes I think it just gets stuck after years of disuse.

 

[alpha eddy]

yea.. the vaccum really bugging me.... but here in sabah, malaysia... i can find from the chop shop the solenoids...i just replace them 2 months ago... all the parts from the chop shop is imported from japan.... the vacuum hose u can use the blue silicon hose.... i already change all the vacuum hose using the silicone blue hose...