Transfer case voodoo please read

[Turdzoplenty]

Hey mudders,
1988 bj74
Vacuum shift 4x4 case.
was running in front of my property, had the tcase in 4wd.
Put in in gear and went to pull away and well, nothing.
wtf.
I can push in the clutch(engine running) and go thru all the gears.
Clutch pedal operates normally, a peek underneath reveals the fork arm is moving.

SO.
I disengage the 4wd(button out). 4wd light stays on.Weird
Put tcase in neutral, then 2wd, unlock hubs. Front drive-shaft is still engaged.again, weird
But no forward movement.

When I move tcase shifter, solenoids click
when i engage the 4wd button, solenoids click.

I figured it may not have enough vacuum to engage/disengage
so while it is running, I pulled off the hose at the booster
and the vacuum is almost nonexistent. Very very weak.

Am I on the right path?

 

[ForealBoreal]

Is this after a rebuild?
Are your vac hoses going onto the transfer correct?
Maybe you have to get your vac pump rebuilt?

 

[3B power]

Best thing to do is to get rid of the vacuum system completely and just run a manual shifter, it just eliminates another problem that can go wrong

 

[John Galt]

Best thing to do is to get rid of the vacuum system completely and just run a manual shifter

Great, show us how you did it.

 

[roscoFJ73]

Best thing to do is to get rid of the vacuum system completely and just run a manual shifter, it just eliminates another problem that can go wrong

Most owners never have a serious problem with them.Its usually a loose hose when they do.
On the right handrive models,the vac shifter means you dont have the transfer case lever hard up against your knee in low range.

 

[Turdzoplenty]

Is this after a rebuild?
Are your vac hoses going onto the transfer correct?
Maybe you have to get your vac pump rebuilt?

It literally was fine one second and not the next.
I will check the vac pump!

 

[Hulsty]

Great, show us how you did it.

Its easy, but pretty much requires a case rebuild to be done, search in the 60 section plenty of threads. My BJ74 now has a manual case with lower ratios. Vac case in both my BJ74 and FJ73 rarely gave issue, only issues were when the 3F ran out of vacuum to run the show.