Lack of 4WD - how to find the problem?

I don't seem to have any 4WD on my 2A - how do i work out where the problem is? Both my levers seem to be moving as they should - yellow knob pops up when it should (I have to roll/drive the landy a bit to re-engage Hi-range, but this happened before it broke and i presume is down to wear somewhere) I have both low and high range, and can drive (in 2WD) in both of them. 4WD doesnt seem to work in either though.

I have free wheeling hubs on the front axle. they are both in the 4x4 position, and i've had them both apart, and they seem to be working, and engaging.

I'm presuming that my problem is either going to be:

transfer box :( front diff a broken halfshaft a FWH not engaging properly

How do i check which one of these it is?

If i was to jack up the front axle/one front wheel, what behavior should i expect when i try to turn the wheel(s)? what else can i do to diagnose it?

At the moment, If i put it in 4WD and low box, then jack up either front wheel, i can spin them both, and nothing else moves. If i jack up both sides of the front axle, I can do the same - both wheels spin independantly and dont move anything else. I was under the impression that one wheel should spin the other, or they should try and turn the prop (which when in 4wd wouldnt be able to turn, cos the rest of the drivetrain would stop it). Is this behaviour implying diff problems, or hub/halfshaft problems?

If i lie under the car at this point, and try to turn the front prop with my hands, I cant turn it far (It has a little bit of movement, but thats normal isnt it?). From this, I gather that my transfer box is infact engaging 4WD. am i right here?

As a back story, which may have something to do with the problems, I had to replace one of my FWH's a couple of weeks ago. I know my 4WD was working a couple of weeks before i did this. I had to replace the hub because half of it went AWOL - the bit on the end that you turn which moves gears around to mesh the hub/halfshaft or not. (I dont know if it fell off, or was taken off - It is held on by 6 little tight (I did em up bloody tight!) allan headed bolts).

Before i noticed my lack of hub, I had driven around for up to 3days (since i last looked at the wheel and saw it intact!) with one broken FWH (so disengaged), and one intact engaged FWH. Could this have damaged something? I noticed that the hub was missing when i did a ~15mile journey, and was getting a clonking noise. On the second stop to investigate it (I intially thought my exhaust was broken..) I noticed that my hub was half missing, and that my wheel nuts were all loose/missing (this was the clonking noise). I know that when i put the wheels on (a couple of months ago), I did em up with my powerbar, but stranger things have happened! Could any of this have done some damage somewhere? Could the diff/halfshaft have got upset when i drove with one hub engaged, and the other not?

Thanks!

Tom

Reply to
Tom Woods
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It's just logic.

You can check the FWH by putting in 2wd High or Low, jacking up one front wheel and turning the front prop, then trying with the other wheel. If one wheel doesn't turn, then that FWH is inoperable. If both wheels fail to turn, then you should suspect the diff. To check the diff operation remove the FWH from the wheels, and check the rotation of the splined output shafts under the same conditions as above. It's possible you've broken one halfshaft, in which case only one of the halfshafts will rotate.

If both FWH and diff are working, then suspect Output Shaft Box. Jack up one side of the vehicle, and rotate one wheel. If the other one does not rotate then the problem is in your gearbox. If you place the Red lever in High, and then depress the yellow knob you should be able to hear an audible clunk as the dog clutch engages. If you hear this clunk, then the dog clutch is moving correctly, but the teeth may be missing, and it still fails to transmit drive

Therefore: Either: broken front output shaft, or failure of the 4wd dog clutch to engage the front output shaft. In either case you're going to have to have it apart to have a look, which means removing the Xfer box from the vehicle.

Alex

Reply to
Alex

I wasnt far off with my guesses! :)

That sounds logical!. I shall jack it up and try turning the prop tomorrow. From what ive read and done so far I reckon its the diff, could be worse i suppose.

I have just got some spare LWB axles, and was thinking of putting them on as a brake upgrade. typically, the only bit i was going to use off mine was to be the diff (dont think my engine will move my landy with high ratio diffs on)

I've never noticed a clunk before when putting it in 4wd, not when it was working, or with my last gearbox.. I suppose its because ive always had the engine running at the time :) will do this test if necessary.

I hope its not the transfer box. The gearbox in there now is the one i put in a few months ago to replace my last one, on which the transfer box makes nasty grindy noises (but works!). Looks like i may have to be brave and rebuild one of them...

thanks for your help.

Reply to
Tom Woods

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