I have a 67 fj40 and the front drive shaft is not turning even if i put transfer case in low gear and pull out the vacuum switch. If i lock the hubs the drive shaft turns but no fwd.
4x4 not engaging (1 Viewer)
- Thread starter Wetlandman
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The collar in the front nose of the transfer case is not moving to engage front drive when you pull your vacuum switch. Likely, no vacuum to the diaphragm.
Make sure you can engage the collar manually first. Then, trace the system from the one end or the other to find the culprit. If you have vacuum to the diaphragm, the diaphragm itself may be leaking.
Make sure you can engage the collar manually first. Then, trace the system from the one end or the other to find the culprit. If you have vacuum to the diaphragm, the diaphragm itself may be leaking.
- Thread starter
- #3
Thanks for the reply! I met my buddy w a range rover at the sand dunes to see whos rig performed better and well i got embarrassed w no 4wd!
Is the diaphragm inside the housing bolted to the transfer case? There is strong vacuum going to the T case. Is there a way to engage the collar manually without taking it apart?
Yes, the diaphragm is in the housing bolted to the front output housing. If it worked in the past, you could try putting it in 4wd and jiggle the front shaft and see if it engages. Maybe its a case of deferred maintenance. Otherwise, it has to come off to diagnose.
This may help
www.sor.com
This may help
Land Cruiser Vacuum Transfer Shift Assembly, FJ40, FJ45 and FJ55
Land Cruiser Vacuum Transfer Shift Assembly, Lever Assembly, Vacuum Switch Assembly, Diaphram Assembly, Vacuum Diaphram Assembly, Vacuum Switching Valve
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John
On the 66 thru ‘71 vacuum transfer boxes all the moving parts are internal, so your idea won’t work.
To isolate whether it is a vacuum problem or a mechanical one, you CAN remove the six shallow bolts from the linkage cover and THEN move the linkage forward manually. Bob Brewer ( from PMC) and I learned this at the same time, in 1986, on the Dusy. Epic trip.
jim land
SILVER Star
You can also convert it to full manual and never have trouble in the futur
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Technically true, but lacks full disclosure.
Once I fixed the vacuum problem I had...in 1986...I have never had another problem with the system.
And in the meantime I discovered how much noise floorshifters make, vs vacuum shift, which make none.
jim land
SILVER Star
True , but I just dont like (trust) switch oparated 4x4
In the 67-71 3 speeds should the front drive shaft spin all the time even in 2wd?
No your vacuum unit is malfunctioning or the engagement collar is stuck.
It will if you have the solid flange instead of locking hubs, or your hubs are locked in.
- Thread starter
- #14
Well i opened it up and used a small pry bar to work it back and forth several times. Fired her up and watched it engage and disengage several times using the pull switch. Then ordered a new gasket, glued it and screwed it and now still no 4x4. 
could it be something in the hubs? They turn okay.
could it be something in the hubs? They turn okay.
Living in the Past
SILVER Star
I would have cleaned and lubed the inside of the vacuum switch pictured. Personally I would have replaced it.
Move you hub to free wheeling and engages the transfer to 4WD. Checked the front driveshaft. Should not spin and then move when back in 2WD it should spin. Now with the transfer in 2WD lock the hubs and try to spin the driveshaft. Should not move if both hubs engaged.
Move you hub to free wheeling and engages the transfer to 4WD. Checked the front driveshaft. Should not spin and then move when back in 2WD it should spin. Now with the transfer in 2WD lock the hubs and try to spin the driveshaft. Should not move if both hubs engaged.
- Thread starter
- #16
I lubed the inside and it seemed to work well when i pulled and pushed in the 4wd knob, but 4WD it is not working.
When in 2WD w hubs locked. the driveshaft will not turn by hand.
When in 2WD w hubs unlocked, the driveshaft will turn freely by hand.
When in 4WD with hubs locked, and I drive, the driveshaft spins.
When in 4WD with hubs unlocked, and i drive, the driveshaft does not spin.
It must be something in the transfer case. Could it be anything other than that cylinder not moving?
When in 2WD w hubs locked. the driveshaft will not turn by hand.
When in 2WD w hubs unlocked, the driveshaft will turn freely by hand.
When in 4WD with hubs locked, and I drive, the driveshaft spins.
When in 4WD with hubs unlocked, and i drive, the driveshaft does not spin.
It must be something in the transfer case. Could it be anything other than that cylinder not moving?
Living in the Past
SILVER Star
How are you verifying it's not in 4WD? Hopefully more than the light on the dash.
- Thread starter
- #18
Now that you mention it. the light on the dash is not working, assumed it was the bulb, but I wonder. I know it is not in 4WD because the driveshaft does not turn when i drive unless i lock the hubs. I also know because I almost got stuck a few days ago and the front wheels never spun. i also know because I can turn on pavement with no issues when 4WD knob is engaged.
I should mention that this thing sat in a barn for 20 years. I am just now driving it and only had it off-road a couple times. For 5 years, I have been one more part away from being 100% drive-able. I have replaced nearly everything that moves and this is the newest one more thing that is broken.
When you verified movement, was it the actuator on the vacuum unit or the collar in the front nose cone that moves to lock the two parts of the front output shaft?
Based on your description of when the driveshaft moves and when it does not, it sounds like the collar in the nose cone is stuck.
Based on your description of when the driveshaft moves and when it does not, it sounds like the collar in the nose cone is stuck.
Living in the Past
SILVER Star
