Knocking noise from drive train P38

Just last night I have a knocking noise from the drive train on My P38 Diesel Auto matic. It varies with road speed at was getting worse on a 50mile trip back All prob UJ's seem ok , but knocks approx every prop turn and not every wheel turn, Any ideas?? Thanks again

Ive had the same problem, i checked the prop and universal joints but couldnt find anything, i went to landranger services and he said it was my uj on the front prop, so i took it home and parked with the front wheels straight WITHOUT hand brake on and in neutral on the auto box, then i "wobbled" and shook the props and found that the UJs where totaly shagged, didnt find first time as when the handbrake was on and in park it kept tention on the prop, hope this helps.

Will have a check at that tonight. Hopefully will be something as simple as that , thanks

A bit of an update for anybody it may help.

Put the RR on wheels free on the ramp tonight and found the knocking coming from the rear diff.
Disconnected the rear prop and turned the diff by hand.
Can hear a knock on every revolution of the crown wheel.
Removed diff oil and visually checked all crown wheel bolts through the filler plug hole and all seem intact.

Diff to come out tommorow ,

Any thoughts?? or does anybody have a spare rear diff from a 1998 2.5DSE automatic?

Thanks

While you are at it, check the viscous coupling hasn't siezed.

Datatek said:

While you are at it, check the viscous coupling hasn't siezed.

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Good thought, but rear diff is in permanent drive and takes most of the wear from towing etc. Seized viscous will do the front diff long before it affects the rear one, because of the differential rotation side to side caused by steering. Sounds like one of the taper cages and or rollers has a notch in it. Pretty common. Or a tooth has come off the pinion. Also pretty common. New diff then. About £250.00 or so from Crowdiffs. Good bloke but still owes me my £50.00 surcharge. Rum bugger.

wammers said:

Good thought, but rear diff is in permanent drive and takes most of the wear from towing etc. Seized viscous will do the front diff long before it affects the rear one, because of the differential rotation side to side caused by steering. Sounds like one of the taper cages and or rollers has a notch in it. Pretty common. Or a tooth has come off the pinion. Also pretty common. New diff then. About £250.00 or so from Crowdiffs. Good bloke but still owes me my £50.00 surcharge. Rum bugger.

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Yes I do know that, but it's still worth checking

Datatek said:

Yes I do know that, but it's still worth checking

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How the hell did you know that Steve Howarth owed me £50.00. Your not mystic Megs lad are you?

wammers said:

How the hell did you know that Steve Howarth owed me £50.00. Your not mystic Megs lad are you?

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No answer to that I was talking about the VC but then you knew that

Datatek said:

No answer to that I was talking about the VC but then you knew that

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Yeah i did to be fair and the viscous is always worth a check but it is highly unlikely that a seized viscous will effect the rear diff without causing lots of damage elsewhere first. I am sure your aware of that it's just that others may not be.

Just a bit of an update guys, I have removed the rear diff and to my surprise found 2 teeth missing from the pinion.

No signs of wear on the crownwheel or on the broken teeth.

Found them in the bottom of the axle casing.

Looks like metal fatigue rather than wear, Is this a common problem?

Also anybody have a crownwheel and pinion set for sale of a complete diff.

Thanks again for your help