Should my wheels move like that?

==EDIT: This bit is now understood, and I can confirm I'm a numpty, please skip down to the tapping noise part, thanks.. ==

Ok, this is likely to be a numpty question. I'm a bit jet lagged and can't quite work out if this is normal, or an issue. Please note I'm relatively new to mechanics, I've had my Landy for 3 years, and its the first vehicle I've tried to do most things myself on. I really am learning as I go, but I'm learning a lot, and doing quite well!

I was doing a few jobs on the landy on Saturday, including trying to hunt down a tapping noise (more on that later) and doing some yearly oil changes underneath.

I don't have a level driveway, so I often (as in this case) I face the landy (90) down hill, put it in reverse, chock the back wheels, and jack the front axel up on stands to level it out when doing things like oil changes, etc.

While it was up, and because I'm trying to find the source of a new noise, I checked out the front wheels, and discovered that my front passenger side has a small amount of play in it. I'll need to take the wheel off to see if this is bearing, or CV or similar related. But I needed to going out green laning, so I just had to leave it as an unknown for now.

But, while I was doing that, I gave the wheel a spin too. And this is where my understanding was off I think. The wheel span fully, there was a slight knock but then it continued to spin freely. I was absolutely expecting it to get stuck due to it being engaged in reverse, but it didn't matter which way I span the wheel, it would continue to spin.

Looking underneath, I could see that the wheel on the opposite side was moving in the opposite direction. So at the very least, that part was working as expected! But maybe I'm completely wrong here, I was expecting the wheel to turn the diff, the diff to turn the front prop and the front prop to get stuck against the reverse gear? Instead, that knock is a "slight" engaging of the front prop, I see it turn for a moment, and then the front diff "slips" on it, leaving the prop stationary and the wheels spinning freely.

Please tell me I'm going mad, and that this is totally expected and normal? Or have I got something broken somewhere in the front diff?!

==EDIT: the rest is the TAPPING NOISE, which I still need thoughts on please... ==

Right, while I've got you all here though, let's talk about my new noise. I first noticed it about 2 weeks ago. it was a gentle tapping/pulsing after shifting into 3rd from 4th at high revs, I.e. slowing down a bit for a fast corner, dropping down a gear into 3rd, and as I lift the clutch, the tapping is there in amongst the sound of the high revs (once clutch fully released), until the landy has slowed down into a more normal rev range for that gear... then it's gone.

It wouldn't do it from 3rd to 2nd, or 2nd to 1st, nor was it present in low range gears.

Part of me was like "I bet that's some wear on the 3rd gear, it may always have been there, but I'm only noticing it now as I'm eliminating so many other noises recently and everything is running so nice and smooth"

Fast forward to yesterday, and I was out for a full day's green laning. About half way through the day, the tapping was starting to get a bit louder, under the same situation. Landy paranoia starts to kick in - "whatever it is, is getting worse! Is this something to do with what I noticed on my front wheels yesterday??".
But it wasn't long until I was certain it was getting worse. It started to do it from 3rd to 2nd too! and then to my horror, I noticed it was present throughout nearly all of the 3rd gear rev range - always tapping in 3rd (subtle, but noticeable). Then the final symptom kicked in... I could start to hear it in low-range gears too, mainly in 3rd again, a little in the higher end of 2nd.

By the time I'd driven it around for 5 hours, and then another hour to get home, the tapping was very very noticeable in 3rd gear.

So, does anyone want to guess at what it might be? Do we think the play in the front passenger side wheel is related? Or is this something even worse, in the depths of my gear or transfer box?

EDIT: here's a recording of the sound:



Thoughts please.

Shimsteriom said:

Difflock not engaged?

Click to expand...

No, not engaged.... but I would have thought that has no impact at the "diff end" of business, isn't that just a change in what happens at the transfer end?

I'm probably completely wrong here, and it's perfectly normal for the wheels not to turn a prop, and this is all part of the wonderful design of the diff - i.e. when a prop is turning, it turns the diff, which turns the wheels, but if the wheels are being turned by rolling, that doesn't mean the diff will turn the prop?

Yeah sorry, I misread your post so have removed my comment now

If BOTH wheels on an axle are off the ground I think the prop doesn't move and the other wheel spins in the opposite direction (Crown & pinions).
The Knock, was the initial slack being taken out of the propshaft spline connection to the diff and then the other wheel began to rotate.

DanClarke said:

If BOTH wheels on an axle are off the ground I think the prop doesn't move and the other wheel spins in the opposite direction (Crown & pinions).
The Knock, was the initial slack being taken out of the propshaft spline connection to the diff and then the other wheel began to rotate.

Click to expand...

Phew, ok - I've just been reading as much as I can again about how a 3-diff 4x4 system works, and going round in circles about this. But, basically, I shouldn't have been worried about that then - it's normal.

So, back to my tapping noise then?

HeywoodFloyd said:

Phew, ok - I've just been reading as much as I can again about how a 3-diff 4x4 system works, and going round in circles about this. But, basically, I shouldn't have been worried about that then - it's normal.

So, back to my tapping noise then?

Click to expand...

IF the propshaft has a higher resistance to turning (the vehicle is in gear) than the other wheel that is hanging in space with no contact with the ground, as soon as the slack is taken up in the drivetrain and it hits the resistance of the stationary engine (Clunk), then moving the "other" wheel is easier than trying to turn over the engine, so the other wheel moves in the only direction it can with the rest of the drivetrain locked against the stationary engine.
I'm sorry, I have no idea what your noise could be, can you get a video showing gear engaged and the sounds on the clip? Upload it to youtube and post the link to it here for the guru's to have a listen to?

Both wheels off the floor and you turn one wheel the diff will take the path of least resistance and either turn the other side wheel or the prop.

Have you checked all the trans oils levels?

lynall said:

Both wheels off the floor and you turn one wheel the diff will take the path of least resistance and either turn the other side wheel or the prop.

Have you checked all the trans oils levels?

Click to expand...

Yep, that's what I've been doing last couple of weeks, doing oil changes across everything. Oil levels were good in gear box, transfer box, front and rear diffs.

Anything else oil related I should try?

UJ's always first thing to check

HeywoodFloyd said:

Yep, that's what I've been doing last couple of weeks, doing oil changes across everything. Oil levels were good in gear box, transfer box, front and rear diffs.

Anything else oil related I should try?

Click to expand...

I assume the box is an lt77? if so did you also remove the filter gauze?

If not sure lt77 is reverse left and forward, r380 opposite

lynall said:

I assume the box is an lt77? if so did you also remove the filter gauze?

If not sure lt77 is reverse left and forward, r380 opposite

Click to expand...

Yep it's an lt77, and yep I replaced the filter (see my other recent thread about the filter plug being cross threaded)

Ok, here we go, a video of the sound..... This is in a straight line, going reasonably slow on flat ground. I'd driven around for 10 minutes without it making this sound, then, after these 2 incidents of it, I couldn't get it to do it again despite driving about for another 10 minutes or so. Yesterday though, after several hours of driving, it was fairly constant. I'm guessing it gets worse when either oil has thinned out or metal has expanded or something...

I'll get out there and inspect the props in the morning - I did take a look a few months ago, all was well and I greased them up a bit through the nipples. I guess something could have developed since then though.

Certainly sounds that way.

Either UJ's or (don't laugh) your green laning has shifted your exhaust and that sound is your exhaust in contact with your chassis or bodywork somewhere.

DanClarke said:

Either UJ's or (don't laugh) your green laning has shifted your exhaust and that sound is your exhaust in contact with your chassis or bodywork somewhere.

Click to expand...

However unlikely, all avenues must be investigated. I'll add it to the list to take a look at in the morning. Thanks!

Looks like it's going to be a CV Joint. I've inspected just about everything, so I'm back to the play in my from left wheel. Basically, with the wheel off, I can tell that the shaft has play inside the stub axle.

So, I can see that for my axle, there's 2 types of CV joints, depending on how many splines the diff has. Is there anyway of telling this though without taking off the stub axle and pulling the joint and shaft out and looking on the diff end? I'd rather order first, and take it all off and replace in one job, rather than take it apart, find out what version, then wait for part to arrive and put it in (the lack of daylight hours is impacting how much spare time I have to do all this).

Or is this as simple as how many splines there are on the hub end (of which mine has 24)?