Engaging 4 Wheel Drive Issue

[trguy75]

I am still relatively new to the Land Rover Series IIA and have not used the four wheel drive since I bought it a year ago. It engaged and worked when I bought the car, but now a year later I tried it again and the yellow knob engage lever will not stay in the depressed (engaged) position. It jut pops back up when I push it down. I read the manuals and seem to recall it stayed down by pressing it down. Am I missing something here or did something break? Thanks in advance.

[SafeAirOne]

Either the right-most (4-wheel drive) shaft or the center (pivot) shaft is gunked up or the dust cap on the nose of the transfer case that houses the tips of those shafts is damaged and not allowing the shafts to extend into the dust cap.

When you push down the yellow 4WD knob, a holding pin is withdrawn from the pivot shaft, and the center and right side of the pivot springs forward, bringing the 4wd shaft with it, and engaging the 4wd "gears". The left side of the pivot is held stationary by the high/low selector shaft.

It's what happens in the first 4 seconds of this video (note: perspective in this video is from forward below, looking aft):

If the rods are gunked up, you may be able to hold down the yellow knob while you cycle the red lever, or keep the yellow knob up and cycle the red lever or a combination of these, to free it up.

If not, remove the dust cap that enclose the ends of those rods on the front of the transfer case 4wd housing to try to free them up:

Dust Cap by SafeAirOne, on Flickr

[o2batsea]

in high range (red lever forward) you push down on yellow knob. You can be moving or stationary. knob should stay down indicating 4wd is in. Limit on road speed to about 30 mph to reduce tire wear. To disengage, stop, move red lever to low position, then back to high. Yellow knob will pop up.
To engage 4wd low, stop vehicle. Gearbox in neutral. Move red lever to the rear. 4wd automatically engages. Disengage as above.

[SafeAirOne]

in high range (red lever forward) you push down on yellow knob. You can be moving or stationary. knob should stay down indicating 4wd is in. Limit on road speed to about 30 mph to reduce tire wear. To disengage, stop, move red lever to low position, then back to high. Yellow knob will pop up.
To engage 4wd low, stop vehicle. Gearbox in neutral. Move red lever to the rear. 4wd automatically engages. Disengage as above.

I went straight to a mechanical fault--I didn't even think about the (im)possibility of attempting to get the yellow knob to stay down with the red lever all the way back in 4 low.

[trguy75]

Thanks for the responses. I have tried cycling the red lever back and forth and also while holding down the yellow knob. No luck. If I am reading correctly, by moving red lever to low range it should automatically go into four wheel drive. It doesn't seem to be doing that either. It worked 100 miles ago which is a year ago. Just haven't needed to use it. I will read up on removing dust cover to see if it can be loosened up.

[o2batsea]

Give Stephen Peters a call. He's at Safari HP in Disneylando.

[S11A]

I had the opposite issue - wouldn't stay up. Viagra in the fuel tank didn't help so I pulled the floor panel and removed the cap Mark indicates in the drawing. Turns out the transfer case was just fine but the (alleged) mechanic that did some other work did not assemble things correctly. I took things apart to where I could see the rods moving, couldn't see anything wrong, and so just put it all back together since I didn't think I could get back to it for a while. Putting it back together in reverse order of how I took it apart made no sense so I just assembled it as did make sense and lo and behold, it did work. (Later dug out the green bible and confirmed the 4wd shift lever and springs incorrectly hooked up.)

I know you didn't take yours apart but the moral of the story is it just a minor amount of wrenching to remove the floor panel to see what is actually going on. Maybe you will find something simple like a linkage rusted or a cotter pin fallen out.

[trguy75]

Thanks for the responses and contact info for Safari HP in Orlando. I will keeping working on it.

[antichrist]

Do you have free wheeling hubs in the front that are unlocked?
I'd put it securely on 4 jack stands and observe what the propshafts are doing, if anything, when the red lever is fully forward and fully back.
My bet however is on rust in something if it's been sitting for a year, assuming it really did work when you bought it.

I have seen the dust cover dented when driving in 2WD and so it then won't go in to 4WD.

[adelafofca]

I know this is an older thread but I am having the same problem: I can't get 4WD High to engage. 2WD Low it works fine. I tested it by lifting the front end and the driveshaft is engaged. I removed the dust cover and everything worked. With the 4WD pin up 4WD High was engaged and the 4WD selector came out the full length per the manual. When I put the dust cover back on 4WD won't engage. I cleaned out the cover and removed all the gunk so there shouldn't be something restricting the 4WD selector movement. Anyone run in to this issue?

My only other option is lubing that shaft but assume it gets lubed from the oil thrower on 4wd shaft spinning. Since it moves when I go in to 2WD Low then the spring on that shaft must be working.

Any help would be appreciated.

[jimrr]

sounds like the shaft is impeded. also measure the throw on the 'pin' with & without the cover.

[roverp480]

I agree , if it works OK without the cover and then not with it fitted something with its location or fixing is impeding it. I think you need to take it off again and check. It may be worth slacken off it fixings & see if it starts to work.

[adelafofca]

I measured the travel of all three shafts with the cover off and in each mode. They checked out per the docs I found in the forums. It must be something in how the dust cover is mounted. I did find that I only need to remove one side of the floor to to get to it and not the tunnel.

I can't think of anything else that would restrict it.

[jimrr]

i guess you could be in Maine or Alaska and you have some ice in there?

[adelafofca]

I found my issue. The 4wd pin wasn't moving upward enough from the yellow lever press to release the selector. I adjusted the rod that connects to the pivot as much as I could. It requires a full, hard press own to release the pin, but it does engage. Not sure if there are other adjustments I can make to ensure it engages when I need it.