noise diagnosis

[steve_a]

Bit of an old one I know but I thought I would look for any information as to find out what is causing a very disturbing noise before I do loads of work.

def 90 with TDi engine.

The noise is intermittent and is 'rotational' i.e. only happens when the wheels are in motion and is road speed related. Dipping the clutch and putting in gbox neutral the noise is still there.

Current known issues:

(quite a lot of) Play in drop arm ball joint (getting done on Monday fingers crossed) - don't think is the cause?

Front axle:

Play in diff nose, it can be waggled, it's not the UJ as they are new and the play is actually on the flange. Play disappears or reduces after driveline slack is taken up by turning the prop. It almost appears to screw in turning anti-clockwise.

Play in swivel pin - on my jobs to do this month, however as a stop gap i removed the shims and padded the thrust washer to remove play for the MoT. This was done just before the noise started. However this can't cause it can it? since it doesn't affect rotation, and to do the job I just took the top pin out, unless I have moved the hub assembly far enough that a CV catches sometimes???

Front CV, left I think is in need of changing, right I am positive needs renewing, going to do the job during the swivel pin change.

So my plan was to look at dropping the front prop off and taking off the drive flanges on the front wheels, this should isolate the front axles diff and CVs, if I still get the noise it is obviously transfer box or rear axle then? Is that the way to do it?

Assuming that the noise is the front axle, how can I tell if diff or CVs? I think I already know what's gonna be said, take the drive shafts out, which will mean I'll tell if it's the CVs anyway.

Since the noise just comes and goes it's difficult to pin down, however this morning it seemed to come on a gentle bend at 30-40mph, which makes me think it is the diff, as a u turn doesn't seem to have any clicking or banging from CVs. The diff is obviously running fast and any problem would show up more during a 'high speed' corner rather than slow hard cornering?

I have a spare diff, so I was thinking about just putting one in when I did the swivels, however it will mean I will have to dismantle both sides at the same time won't it?

finally the play in the diff nose, this is presumably the bearing and crushable thingy that needs replacing isn't it? It is leaking some oil. Oh, I did also check that the diff had oil in and while ugly and needs changing it was full.

[Phil Hancock]

Front axle:

Play in diff nose, it can be waggled, it's not the UJ as they are new and the play is actually on the flange. Play disappears or reduces after driveline slack is taken up by turning the prop. It almost appears to screw in turning anti-clockwise.

finally the play in the diff nose, this is presumably the bearing and crushable thingy that needs replacing isn't it? It is leaking some oil. Oh, I did also check that the diff had oil in and while ugly and needs changing it was full.

The flange will appear to screw in when the drive goes on forwards as its a spiral bevel drive.

There is no 'chrushable thingy' on a rover diff only on a Salisbury type, preload on rover type is by shims. The leak will be caused by worn seal and the play you describe being more than the flexability of the seal being able to cope with.

The noise is as the pinion is screwing in under forward load/overun the clearance between the ring and pinion has gone and they are then binding.

Replacement diff time is the simplest if you dont know how to set them up.

[chuggaman]

just done my rear diff

take off the front prop at the diff end.if you can move the flange in a side to side or up and down,then your pinion bearing is shot.

i resolved this by getting a s/h diff and rebuilt my locker into that.

good luck

mike

[steve_a]

As usual it looks like it is a combination of things. The left bearing failed yesterday (made quite a mess too) there was no warning about it because I am pretty sure it was caused by my bodge of the swivels, I think it caused the CV to bind in the chalice, at least on reassembly it all went tight and I couldn't turn the hub, so I removed the packer and it was back to normal.

On top of this I had missed that the chalice to axle bolts were loose, the bottom half had about 3mm showing, it was probably this combined with my tightening that caused the failure, I am convinced this was the noise.

From what you are saying mike then it looks like it might be time to swap the front diff out for one of my spares and fix or sell the current one. There is play up/down/left/right, I wonder if this could be a lot of the play in the drive train then.

Phil, you're right, on the rover diffs there is no crushable spacer/washer, I think the last time I looked at doing the oil seal it was on my friends 110.

MoT failed it on the drop arm joint, as expected, and the rear A frame ball joint, because the two wings are badly rusted, I did suggest that considering the effort to get them in and out that those wings didn't make a lot of difference, but you can only argue so far. So garage will be doing both those jobs, pain and grief is too high to do them just at the moment.

Also failed for a hole on the drivers footwell My rubber mat had too much structural integrity so I hadn't noticed it

Bad news is I am pretty sure I am going to have to do the swivel pin railko and bottom bearings on both sides before I put the truck back in for the test.

Expect rain all week

Thanks for the input

Steve