AWD or 4WD?

[izack98]

I went in today to get my '97- L400 Air Cared. They asked me if it was AWD or 4WD. I responded 4WD as I believe that's what it is. He confirmed by asking if it was 'Selectable'.
They drove it on with just the back tires on the rollers. When they began the test it was obvious the front wheels were pulling as well. They ended up putting it on the 2 sets of rollers as you would an AWD. When they did the test both axles were driving.
The 4WD selector was in 2H. And the 'Super Select 4WD' diagram on the dash indicated green lights on the rear axle only.
I don't understand. All the other manual 4WD vehicles I have had don't drive the front wheels when in 2WD.
I back up into my driveway about 40-50 feet each time I park so I assume this is enough to unlock the front hubs. I haven't had it in 4WD for quite awhile.
I haven't tested for awhile, but when I did a couple of months ago the rear wheels spun on gravel so the front hubs weren't locked. (I'll test again when I get a chance).
Anyone else had this issue?
Any ideas? Suggestions?

[chris]

Stock hubs don't unlock. They are permanently locked. When you select 4H or 4x4 with the lever, you are mechanically engaging the front drivetrain through the centre diff. The linkage under the shift lever boot can break or get stuck. It's only a few bolts to undo to check. As for your lights, check to see if any are burned out by shifting into 4x4.

One thing I don't get - if the front wheels were pulling when the rears were on rollers, wouldn't the van have driven off the back roller and caused mayhem?

[izack98]

Ok, I figured the hubs wouldn't unlock. But, in 2WD I didn't think there would be any driving force produced through the transfer case to drive the front wheels. If this was the case then I shouldn't be able to spin the rear tires on gravel when in 2WD should I?
I will find some gravel and check this tomorrow.
All the lights work. The other 2 green lights for 4WD light up when I shift into 4H.

Re: The mayhem - I guess they have encountered this before. They put blocks in front of and behind the front tires. Then they loaded the drive train by accelerating a bit. They could see that the van was about to drive forward. So they backed it up and put both axles on rollers.

[Mr. Flibble]

When you are fully in 2WD, your front wheels should not turn from anything other than road friction.

The L400 is selectable:

2WD-AWD-4WD-4WD low.

You were probably still in AWD.

[izack98]

Nope, I was in 2WD. I had not touched the selector lever, and a couple of days later I accelerated on some gravel and got the rear tires to break loose. I don't know what was up but all appears to be working normally.
It wasnt a big deal to the aircare people, they just readjusted. I was just wondering what was up with it.

[Big-Bird]

I had this happen when I first got mt L400.

I was playing with the 4WD system to see what worked and how it worked in a parking lot.

I was parked and shift to 4-Hi. Drove forward 20 feet and then stopped to shift back in 2WD.

The lights showed everything disengaged back to 2WD. Then I loaded up the drive train (aka brake stand style) to see what RPM the real wheels would break loose. All 4 started to spin on the wet/icy ground.

Seems the 4wd had not fully released. The vehicle needs to move in order to fully release the 4wd gears/solenoids that engage the system. I moved forward a few feet and tried again, this time only the rear wheels broke loose.

Perhaps the shifter was bumped into and back out of 4wd?

[Mr. Flibble]

Sometimes you have to go in reverse or pop it into neutral to disengage the AWD.

It is not always apparent. But you learn to feel how the wheels pull when in AWD and you can adjust for that.

Just because the lever is in 2WD does not always mean it has left AWD.