4wd vacuum

[Ian Sharpe]

Gidday all,

trying to find a way to allow 4L but without the front wheel drive being activated. Useful for when low range required but on hard surfaces.

Dealer says cant just control the solenoid with another switch as this will confuse the entire system.

There was a post on one of the forums about this some time ago but I cant remember which one.

anyway, anyone got any ideas??

Dealer also says there is vacuum in the line in 2wd & none in 4wd. Is that correct or is it the other way around?? this will determine how to doctor the system.

any advice appreciated.

[-Scott-]

I believe no vacuum in 4WD - I recently ran out of fuel and tried to switch off the ignition while coasting to a stop - it made a dreadful noise, which my friendly ARB man (and long term Mitsubishi Club member) said was the front diff trying to engage?

What's to confuse? So the switches don't all say the right thing - gunk in the switches causes that anyway! I wouldn't worry too much about the dealer's comments...

Scott

[DougH]

I believe no vacuum in 4WD - I recently ran out of fuel and tried to switch off the ignition while coasting to a stop - it made a dreadful noise, which my friendly ARB man (and long term Mitsubishi Club member) said was the front diff trying to engage?

What's to confuse? So the switches don't all say the right thing - gunk in the switches causes that anyway! I wouldn't worry too much about the dealer's comments...

Scott

The central axle disconnect is spring operated as far as I know. The vacuum keeps it in 2wd, not the other way around. I could be wrong, but from looking at the parts diagram, and testing I think this is correct.

If you lose vac, or you turn the truck off it will engage the CAD.

I dont see the main purpose... you will lose half of your torque, since it will still be transmitted to the front of the tcase in a 50:50 split.

The only way would be to install dual shifters that shift the axles independent of each other.

[Ian Sharpe]

thanks guys,

the main reason is to allow low range on ard surfaces but without the windup that would come with 4wd.

[Bitsamissin]

The easiest way to do this Ian is to fit Aisin manual hubs from a base model diesel or Triton.

[Ian Sharpe]

Frank,

yes I thought of that one, just leave them locked all the time & viola NO change to existing system, unlock them when no front whel drive needed.

But there also must be a way to do this with switching solenoids etc

[-Scott-]

I had this wierd idea about the Patrol's Auto-locking hubs. They have an "Auto" position and a "Locked" position, so you don't have to worry about them disengaging during hardcore wheeling. Are they vacuum operated in the Auto position?

Getting complex again, and I've also heard they're not terribly strong...

Scott

[Bitsamissin]

There is a way of doing it and it has been done.
Chris Robinson of NZ has a Gen 1 lwb and he welded the front diff up.
He used a super select front diff with all the solenoids etc and rigged up a switch on the dash that he uses to engage the front diff. He can easily disengage it when he has to turn the corner works like an ARB locker in a defacto sort of way.
There is a write up in the Trail Talk (Mitsu) featured vehicle section in the archives somewhere.

[J Top]

Doug
I don't see how you lose any torque with no front axle drive.
You are increasing the loads on the rear diff and axles by applying all the power this way instead of spreading it between the two diffs.

Ian , I'm with you .I have a 4wd garage with an access ramp which I have to push dead vehicles up.I use a bar with two tow couplings and back them in with my J Top in low range which does give wind up as I jack-Knife them in.
J Top

[J Top]

Doug
I don't see how you lose any torque with no front axle drive.
You are increasing the loads on the rear diff and axles by applying all the power this way instead of spreading it between the two diffs.

Ian , I'm with you .I have a 4wd garage with an access ramp which I have to push dead vehicles up.I use a bar with two tow couplings and back them in with my J Top in low range which does give wind up as I jack-Knife them in.
J Top

[Adomw]

Ian

Despite what your dealer says, you can (and I have) just control the Vacuum relay.

On the NJ Pajero the vac solinoids are under the power steer fluid reservoir. I found them by following the vavuum lines from the front diff

The 4WD CPU switches this vac relay to ground so its no drama to fit a manual switch on your dash to do the same.

No problems with mine. and a helluva lot cheaper than fitting free wheeling hubs

Ado