4WD Headaches!! (1 Viewer)

[chui]

HI.
Have a BJ 74 - Cable lockers, manual hubs and the standard H2 and 4L gears.
The H4 button was disabled a number of years ago.
Got stuck this weekend in a huge 'bog' of black cotton soil.
Engaged manual hubs and put gear into 4L.
But nothing..
Back tyres spinning. Nothing from the font two tyres.
Tried, once, twice, three times.
Tried cable lockers..
Nothing. No noise apart from the revs from the engine and the back tyres going crazy.

But the week before I engaged the 4wd system and it worked. I got out of some tricky mud..

Any ideas what may be wrong?

 

[roscoFJ73]

You'll have to try it again and see if the front driveshaft is turning.

I think there is a inkage that automatically puts it into 4wd when you shift the lever into 4L or maybe it triggers the vacuum solenoid.
Either way I think that will be the problem

 

[Radd Cruisers]

The 4WD shift is controlled by two VSVs (vacuum switching valves) that are located on the fender or firewall (model dependent). The push button on the dash operates the VSVs to engage or release the 4WD mechanism.

You should have a look and see if there have been some changes to go to a manual shift, or the VSVs or switch is non-operational. When in low-range, the 4WD should engage if the VSVs are present and working, since there is an over-ride on the transfer case to cause the engagement to happen.

So -

Check the vacuum lines are hooked up to the VSVs and that you are generating vacuum.

Check the VSVs themselves to see if they get power and can switch.

Check the lines and tubing that goes from the VSVs to the transfer case shift mechanism.

You can operate the mechanism by way of a small hand held vacuum pump if you connect it to the vacuum lines that go to the transfer case... you can also use the vacuum that the vehicle generates if you hook it straight up to the lines that to go the the shift mechanism. One tube will engage, the other will disengage...


HTH.

~john

 

[chui]

hi.. cheers for the info..
I put the cruiser up on stands and tested it again. Found out only one wheel (left side) rotates in 4wd. Checked the vacuum switches - faulty - replaced together with vacuum hoses which were cut.
engaged 4wd after locking hubs all went well then they just remained locked.
CAnt disengage 4wd.. any ideas why

 

[Cruiser70]

Have you tried swapping the two vaccum pipe around, maybe one of them is not sucking enough, vaccum pump?
Rear Diff lock can get stuck, reversing fast in first gear usually unlcoks it from that i have heard.
Does anyone know if putting it into low gear uses the vaccum, I assume it does, but maybe there is a manual linkage in the gearbox, I dont know?

 

[chui]

hi.
Had the switches replaced. Nothing.
Opened up the Transfer case. Vacuum / diaphragm was ok.
Then saw the shaft and bearings.. All worn out completely.
Changing those. Expensive..
Lets see... tw

 

[Radd Cruisers]

The shafts and bearings are reasonable in price. I can source these for you if you want.


~John

 

[chui]

hi cheers john.. have gotten them here.. but still issues with the 4wd.. Im actually looking for the H4 button and wiring for the BJ74?

 

[Radd Cruisers]

Post up your address, I'll send you a .pdf of the wiring diagram.


~John

 

[chui]

Hey John cheers for the info.
you can send it to me at
info@sportingconservation.org

Really appreciate..