Should the front differential be spinning when in 2wd? (1 Viewer)

[WhereToRodeo]

1967 fj40. Thats pretty much the whole question. Want to make sure my rig isnt stuck in 4wd...!

Thanks for any help.

 

[Pighead]

no...not if your hubs are not locked

 

[Living in the Past]

If you don't have lock out hubs or the huds are locked it will spin even in 2WD

 

[WhereToRodeo]

I have locking hubs. Uhhg. Umm hmm, i wonder if my hubs are broke and locked in. They spin to 'lock' and 'free' but in supposed 2wd the front diff spins.
Question, can i disconnect the driveshaft for the time being until i try and figure this part deal out or will it spill fluids, etc do you think?

 

[BEE-JAY42]

Simple test. Unlock your hubs and take your car for a quick drive to ensure the locking spline in the hub has unlocked, then with the transfer case in 2wd you should be able to climb underneath and rotate the drive shaft by hand.

 

[brian]

quicker test. jack the front end up and try to spin the front wheels by hand.

 

[WhereToRodeo]

Ok bad news boys. Could not spin driveshaft on ground in 2wd. We jacked the fj up and disconnected vacuum shift valve and still wont come out of 4wd. Any ideas? Do i need vacuum to disemgage 4wd assuming the valve is bad? Aside from that, all i can see is that the front diff is connected backwards, but doubt that would be a problem...

Thanks again

 

[sggoat]

I would think it has to be in the T-case somewhere.

 

[Living in the Past]

Disconnect the driveshaft at either transfer case or diff. The end that doesn't spin is the end with a problem. Taking the shaft off will not cause any fluids to leak.

 

[tyama]

Hiya, I think you're gonna have to take the vacuum shifter unit off the t case and check to see if the donut on the front output shaft is moving freely back and forth. It locks the t case in front wheel drive. If it moves as it should, and your front drive shaft locks and unlocks, there is a problem with your vacuum shifter. To get the vacuum shifter off is a PITA, but it'll let you know what's going on.

Best, ty

 

[Living in the Past]

Ok bad news boys. Could not spin driveshaft on ground in 2wd. We jacked the fj up and disconnected vacuum shift valve and still wont come out of 4wd. Any ideas? Do i need vacuum to disemgage 4wd assuming the valve is bad? Aside from that, all i can see is that the front diff is connected backwards, but doubt that would be a problem...

Thanks again

The vacuum shifter uses vacuum to shift both in and out of 4WD. In the FSM it tells you how to test it. It has a rubber diaphragm and if that is bad it won't shift. On the vacuum shifter they should be a switch that lights up the green light on the dash when it's in 4WD. Does that work on you cruiser? Even broken off wires at the switch it is sometimes possible to use a meter on the terminals where the wires broke off to check it.

Has the cruiser shifted in and out of 4WD for you in the past? It is possible to remove the vacuum shifter and reinstall it missing the grove on the collar that slides on the output shaft. If the fork from the vacuum shifter is behind the collar it will always be in 4WD. If you do remove make sure the fork is in the grove when you reinstall it.

I am curious what you mean the front diff is connected backward?

 

[BEE-JAY42]

Disconnect the driveshaft at either transfer case or diff. The end that doesn't spin is the end with a problem. Taking the shaft off will not cause any fluids to leak.

Do this next, work out where the problem is before you start pulling things apart it will save you a lot of heartache.

 

[Pighead]

I might try something even simpler first...try putting the tranny in reverse and popping the clutch a few times (engine running). works on later models

 

[Howard705]

You can drive it this way too as long as ONE end is disengeged-either lockouts OR t case.
I'm betting vacuum/diaphrabm problem.

 

[want2wheel]

How about pulling a vacuum on the diaphram to see if it will disengage before you start pulling allot of stuff apart?

 

[Living in the Past]

How about pulling a vacuum on the diaphram to see if it will disengage before you start pulling allot of stuff apart?

There are two vacuum hoses. Just pulling the hoses will not cause it to change from 4WD to 2WD. If the problem is a vacuum issue and in the vacuum switch and not the diaphragm switching the hoses might switch out of 4WD if it is in fact in 4WD.

 

[want2wheel]

I was talking about using a hand vacuum pump to pull vacuum on one side of the diaphram or the other to see if the internal shifter would move. I can see that switching the lines could do the same thing.

 

[Fast Eddy]

try putting the tranny in reverse and popping the clutch a few times (engine running). works on later models

Because of this I'm surprised the vacuum shifter ever works. I suppose it just stays locked until "eventually". What if you just want to pull onto the pavement and unlock the hubs later? It seems it would stay locked a lot of the time. Every 4x4 I've ever had had this issue.