Urgent Diagnosis help needed

[Spooky]

Err no, that doesnot sound right.  But looking at the pictures I can't see anything amiss ...

I have a confession Gordon - I've only just seen the PM you sent me ... :oops:  I do apologise - me sitting here all dumb and stoopid whilst you're struggling on.  Sorry, mate!

[Thrasher]

Hmm....

Something isn't right. Rotate the flange and listen for the clonk.

THen back it off, and do it again until you get where it is coming from, also, watch the pin in the middle, see if it is moving around.

[Thrasher]

Well ... if a diff centre is required, my offer stands.

[gords]

Wow, am I confused :shock:  

Should the small inner cogs move round without the big outer one moving? 'cos they do!

Neil - which bit are you offering?

[Thrasher]

Gords,

I have the diff centre, thats the inner bit, without the crown wheel (the big turny bit) ;-)

[gords]

I have a confession Gordon - I've only just seen the PM you sent me ... :oops:  I do apologise - me sitting here all dumb and stoopid whilst you're struggling on.  Sorry, mate!

No worries, it came off quite easily once I'd broken the join (gentle use of trolley jack )

Neil (or anyone) - how does the crown wheel join to the diff centre - as I said, the cogs in the centre turn without the crown wheel turning, so what's going to make the wheels turn when the propshaft turns? :?

[Spooky]

The crownwheel is bolted to the diff centre.

The test is to hold both half-shaft spline outputs, and try to rotate them against each other.  If one turns freely, there's your problem. Just turning one will caused the small cogs to rotate.

[muddyweb]

Gords..

The pinion and pinion gear are attached to the input flange... this is turned by the propshaft.

The crownwheel (the big one) is bolted to the diff carrier and is directly meshed with the pinion gear, so this will always turn.

There are then a few more gears...

The side gears (shown in brown) into which the halfshafts fit
The planet gears (shown in red) which sit on a cross pin

When both wheels have good traction, as the crownwheel turns, the whole diff cage turns as well (the planet gears are working against each other) and the shafts both turn.

When one wheel has less traction, or is turning at a different speed (when cornering) there is a difference in rotation of the planet gears and the power is distributed across the shafts.

Because the planet gears are always working against each other, they need to be secured, and they need to be able to turn freely.

[Thrasher]

Gords,

My diff centre ... http://members.mud-club.com/profiles/thrasher/gallery/Diff

[Spooky]

Neil, I take it that you still have the outer races for the bearings? :?:

[muddyweb]

I think the bearings probably ought to be changed if they are going in a new carrier ;-)

[Thrasher]

I would agree with Tim, my LSD's went in with new bearings and races. I do have the old races, but they will need cleaning up as they have been off the vehicle for over a year in the garage, which aint known for being dry ;-)

Secondly ... there is the possibility the breakage is in the diff nose....between the flange and the crown wheel....!

[gords]

Well, I'm still lost

I just started it up, in normal box and 1st. Car doesn't move but output shaft from the gearbox is turning. I already know that it will drive on the front wheels in diff-lock.

I put both half shafts in the diff and tried various stuff - the only way I could make both half shafts move without moving the crown/input shaft was to turn the half shafts in opposite directions.

Is there anyone who could pop by and take a look please?

[Range Rover Blues]

Gords..

The pinion and pinion gear are attached to the input flange... this is turned by the propshaft.

The crownwheel (the big one) is bolted to the diff carrier and is directly meshed with the pinion gear, so this will always turn.

There are then a few more gears...

The side gears (shown in brown) into which the halfshafts fit
The planet gears (shown in red) which sit on a cross pin

When both wheels have good traction, as the crownwheel turns, the whole diff cage turns as well (the planet gears are working against each other) and the shafts both turn.

When one wheel has less traction, or is turning at a different speed (when cornering) there is a difference in rotation of the planet gears and the power is distributed across the shafts.

Because the planet gears are always working against each other, they need to be secured, and they need to be able to turn freely.

Nice answer.

[muddyweb]

Curiouser and Curiouser...

Were the bolts holding the drive flanges all present and correct  ?
You got any pictures of the halfshafts ?

[Wanderer]

I've never worked on one of the rubber donut props but could the rubber donut have gone so the prop isn't actually turning the drive flange?

Ed

[gords]

Curiouser and Curiouser...

Were the bolts holding the drive flanges all present and correct  ?
You got any pictures of the halfshafts ?

3 bolts, all there and nicely tight - both sides of the rubber donut! Donut looks to be in one piece.

Propshaft slides in and out nicely and the sliding joint doesn't spin round (not by hand at least!).

Some more pictures in my gallery.

Anyone want to buy a 2 wheel drive Discovery? :roll:  

[muddyweb]

Interesting thought Ed...

Looking at the pictures, I'm not sure how it would fail... but I don't *think* it could happen.

[muddyweb]

What about the bolts which hold the driven member (end of the half shafts) ?  Were they all OK ?

[chuggaman]

are you sure its not your transfer box

you know when you change from low to high and sometimes it jumps out into what effectively is neutral(with that loud bang)and you get no drive

just a thought

when you change from diff lock to low or high is there any friction or clunking

[ChrisW]

I've seen a "failed" rubber donut - it's still attached to prop/diff just a helluvalot of play - chap that brought it in was complaining of clonking on taking up the drive not surprisingly  :roll:

Gords - is you're donut still a donut?  :lol:

[Xtremeteam]

are the drive flanges 1 piece & part o the shaft or like the defender 1's & can strip inside the flange?

[muddyweb]

Chuggaman.. I thought that... but if the rear propshaft was turning and the vehicle wasn't going anywhere, then the problem has to be in the rear axle somewhere.

[gords]

Could it be something that only occurs when it's under load (trying to drive the car)?

Lots of bits appear to be quite loose and/or have quite a bit of clearance. e.g. if I hold the flange still and move the crown wheel, the input shaft (whatever it's called) goes up/down a mm or 2.

[Manicminer]

When you turn the drive flange does it turn the worm drive and then turn the crown wheel, or do you turn the flange and nothing happens?

[muddyweb]

It's possible Gords, but I would think you would hear a rattling when you tried to drive.

[Range Rover Blues]

I'm watching with interest.

[gords]

At the time, and a few times since, I have switched from normal to diff lock.

When it first happened, I put the handbrake on and felt that it was stopping the propshaft. When I got it home, I got the wife to put it in gear and accelerate (gently!) while I watched underneath and I could see the axle end of the propshaft going round.

The bolts holding the half shafts to the wheel end (!?) were all there and tight.

I put it into diff-lock and 1st gear and jacked up each wheel individually - both rear wheels rotated, but the front wheel (only tried one) didn't - is this as expected?

[gords]

It's possible Gords, but I would think you would hear a rattling when you tried to drive.

 :shock: ooh, haven't I mentioned that? It did make a clanky kind of noise - kind of like metal banging together. A bit hard to describe, but there was definitely noise associated with trying to drive!

[muddyweb]

I put it into diff-lock and 1st gear and jacked up each wheel individually - both rear wheels rotated, but the front wheel (only tried one) didn't - is this as expected?

With the handbrake on, yes... with one front wheel off the ground and one on it, and the input locked (via the diff lock and handbrake) then the raised one shouldn't turn.

The fact that the rear did points again to a failure in the diff.