4wd limbo (1 Viewer)

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Jun 9, 2021
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Bozeman MT
Hey y’all.

So I had a busted vac line on my 1985 BJ-60 that was preventing my 4wd from working proper for a bit and not the vacuum system is replaced and working and now when I tried to go into 4wd the light came right on but it definitely didn’t fully engage as the front is still free with hubs locked and all the things checked. When driven it makes a slight chatter like the splines are lightly touching but not close to engaged. I have tried running it in all configurations to get it to fully engage or come out but nothing.

I’m wondering if my vacuum isn’t strong enough?

Did the time (winter in ohio… salt) seize something up somewhere?

Any thoughts?
(Checked around and couldn’t find any posts with a similar problem so if there is one in all ears).

Cheers.
 
when the 4wd light is on, the driveshaft still spins by hand?
both hubs locked the driveshaft spins by hand?
 
Was it working before? did you take apart the vacuum shift appartus? Do you know how much vacuum you have?
 
when the 4wd light is on, the driveshaft still spins by hand?
both hubs locked the driveshaft spins by hand?

Driveshaft appears to be locked in. Unable to move by hand at all.

driveshaft won't spin, good, but to which question? it needs to be checked one at a time, not both at once.
the answer will direct my next comment as to which way to go
 
Was it working before? did you take apart the vacuum shift appartus? Do you know how much vacuum you have?

No I should test the vacuum though. It worked flawlessly before. I didn’t use it for a bit then went to run it in some mud and it didn’t engage. I found the disconnected vac line and threw it on and put it in 4 wheel through the proper procedure and now here we are. It is definitely pulling if I put a finger over the line.

I wanted to consult on here before ripping into it good to make sure it wasn’t something dumb I was missing… it’s my daily driver etc.
 
I thought BJ60s had a lever-actuated transfer case, and the HJ60s with auto had a vacuum-actuated one.

Are you sure your truck uses vacuum to shift into 4WD?

Anyway, if your front driveshaft doesn't move with the hubs unlocked, the transfer case is engaging. It may be that your locking hubs need a rebuild. If your hubs are all gummed up, they won't engage the axle properly. They are not difficult to rebuild if need be.
 
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No I should test the vacuum though. It worked flawlessly before. I didn’t use it for a bit then went to run it in some mud and it didn’t engage. I found the disconnected vac line and threw it on and put it in 4 wheel through the proper procedure and now here we are. It is definitely pulling if I put a finger over the line.

I wanted to consult on here before ripping into it good to make sure it wasn’t something dumb I was missing… it’s my daily driver etc.
I saw on another thread that the indicator light very rarel
 
I thought BJ60s had a lever-actuated transfer case, and the HJ60s with auto had a vacuum-actuated one.

Are your truck uses vacuum to shift into 4WD?

Anyway, if your front driveshaft doesn't move with the hubs unlocked, the transfer case is engaging. It may be that your locking hubs need a rebuild. If your hubs are all gummed up, they won't engage the axle properly. They are not difficult to rebuild if need be.
Yes it has the same dash/shifting layout as the 62 with the 4wd button for 4 high then mechanical for 4 low and 2 high.

I replaced the power steering high pressure line and must have disconnected a vac line inadvertently bc it wouldn’t go into 4wd to save its life (had to get pulled out of a snowbank with tail between my legs) I finally found the disconnected line when measuring to replace all vac lines figuring that was good starting point.

That makes sense with what you are saying about the hubs… however wouldn’t it come out of 4wd with the light off and all if it were functioning aside from the hubs?

I know enough to be dangerous but haven’t messed with driveline stuff a lot and need to learn.
 
I'm a little confused. Is the 4wd light now always on? or does it turn on and off when you press the button?

Please report on the following tests with all 4 wheels on the ground.

Front hubs unlocked, 4wd off, transfer case in High, you should be able to turn the front drive shaft by hand.

Front hubs locked, 4wd off, trasnfer case in High, you should not be able to turn the front drive shaft by hand. (it may take 1/4 turn to lock up)

Front hubs unlocked, 4wd on, transfer case in High, you should not be able to turn the front drive shaft by hand.

Front hubs unlocked, 4wd on, transfer case in Low, you should not be able to turn the front drive shaft by hand.
 
I'm a little confused. Is the 4wd light now always on? or does it turn on and off when you press the button?

Please report on the following tests with all 4 wheels on the ground.

Front hubs unlocked, 4wd off, transfer case in High, you should be able to turn the front drive shaft by hand.

Front hubs locked, 4wd off, trasnfer case in High, you should not be able to turn the front drive shaft by hand. (it may take 1/4 turn to lock up)

Front hubs unlocked, 4wd on, transfer case in High, you should not be able to turn the front drive shaft by hand.

Front hubs unlocked, 4wd on, transfer case in Low, you should not be able to turn the front drive shaft by hand.
So yes the light is permanently on right now and as I tried to state earlier I saw they are rarely mistaken. I think you are right on the hubs being the issue/ a major part. The problem persists that the front driveshaft is unturnable in every combo including unlocked and in 2H with no button depresses etc.

What I find odd is why wouldn’t it come out if the hubs were the issue. So there must be something compound going on.

I isolated the sound and am finding it to be in the front wheels and specifically the front driver side (passenger confirmed). So +1 on the hubs.

Needs to warm up a scosch and not be snowy for the first time this winter so I can get into those hubs.
 
the locking hub is not a major part, very easy to dis-assemble and see what is wrong and repair or if no time, replace with new ones from cruiseroutfitters

the light staying lit, most likely means the solenoid/switching valve is bad, you can get around it right now by switching the 2 vacumn lines and it will release, then switch the lines back.

there have been a few write ups about the fix for FJ62's which I'm thinking is the same as your BJ, only issue would be if it is 24 volt
 
If you put the transfer case in neutral, you should be able to tell if the hubs are engaging or not. The transfer case is put into neutral with the transfer case shift lever, and it shouldn't matter whether 2wd or 4wd is selected by the button. If your hubs are locked you should not be able to turn the drive shaft by hand. But when you unlock the hubs you should be able to turn the drive shaft by hand.

Here are some documents that might help:

1678887251756.png
 

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the locking hub is not a major part, very easy to dis-assemble and see what is wrong and repair or if no time, replace with new ones from cruiseroutfitters

the light staying lit, most likely means the solenoid/switching valve is bad, you can get around it right now by switching the 2 vacumn lines and it will release, then switch the lines back.

there have been a few write ups about the fix for FJ62's which I'm thinking is the same as your BJ, only issue would be if it is 24 volt
Thanks a million this makes a lot of sense!
 
So finally got it fixed. Wound up being a hole in the steel portion of line that runs proximal to the exhaust on its way to the transfer case etc. got it replaced and all is well. Wound up finding it with a vac gauge. Even still it wasn’t easy bc of check valves holding vacuum somehow.

Also realized with the resources you all presented that there have been several bypasses and tinkering done on the system in a non proper manner. So going to remedy that now and get it as it should be
 

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