Diff whine after output shaft bearings replaced

Slightly disappointed would be the understatement after this exercise.
Just help replace the out put shafts bearings on my XJR with units from Coventry west which was an interesting adventure and learning curve.
We did the job with the car on a hoist and kept the diff in the cage, no problem there, just fiddly.
The question I need to ask is can the diff spider gears/ CW and Pinnion be disturbed if one of the output bearings are screwed in too far?
We realised that the unit needed to be flush after it had been screwed in about 1.5mm too far, once we realised it didn’t ‘seat’ up to a shoulder we backed it out so that it was flush with the diff housing.
When I took the car to the workshop all that was emanating from the back end was a grumble because I had blown the r/h side.
Now the diff is making a noise like a banshee at times but if I pull out of a side street turning left the noise disappears for a short distance/time and then starts up again.
Also I can ‘play’ with the noise by either accelerating, coasting or having the car on the overrun.
Which to me seems to exhibit classic c/w and pinion trouble?

Any thoughts?

Just an update, had to drive the car yesterday and leaving a side road things went bang really loud and lost drive :frowning:(
Cars in the driveway waiting to be diagnosed.

Just a bit confusing as you have this listed under X300. The side axles on the X300 do not effect backlash or ring and pinion gear mesh. The V8 cars on the other hand are totally different. The axles are in an aluminum housing that not only controls gear mesh but also carrier bearing preload, both of which are critical. It sounds like you have a V8 car, not a X300 from your description. When installing the new axles, did you remove and install the carrier bearing races from the old axles into the new ones? Did you measure backlash before taking apart and set it back to the same specs? There is not much to go wrong with these axles as they are a sealed bearing that the axle turns in. No lubrication required. The spider gears are not effected by gear mesh/backlash.

Hi Dick, this covers up to X358 hence they post here.
I have just emailed Bryan with exactly that scenario, I have just stripped the old units down and looking at them on the bench I saw the cone and I don’t recall seeing one on the replacements.
Looks like a replacement diff is now in order :frowning: SWMBO is NOT happy.

Rebuilt axles will not have the cone in them as it is matched to the carrier bearing. Mixing bearings that have been working together is not a good idea. You have to take your old cone/bearing race out and install in the new one. Very difficult to do without totally taking the old axle apart. . If you put the new axles in without the race for the carrier bearings, then the carrier was not supported and I am surprised it went down the road at all. Installing without the carrier bearing race and then driving probably destroyed the axle bearings as they are not designed to handle side loads. http://georgiajag.com/Documents/V8Axles.html might be helpful from my website on V8 axle rebuilding.

Yep realise that now, would have been good to have had that information with the replacements 20/20 hindsight is good. That’s $2k down the tubes :frowning:

Ok so I have the replacement diff and so far three hours into taking the old one out.
So far wheels off (obviously), h/brake disconnected, Jurid bolts out, all six because I did the wrong ones first :frowning: callipers removed and hung from some brake line clamps onto the ridge running inside the wheel well.
Smoke gun came into play on the exhaust clamps after the centre muffler, they were quite bad, Left hand muffler after the sub frame had to be cut while the r/h one I was able to disconnect, thats been out before.
Springs are compressed and the lower shock bolt is out, the replacement diff has standard shocks so I am leaving the CATS units attached. One problem that I have noticed is that the replacement diff hasn’t got the bracket for the anti sway bar so some work to do there :slight_smile:
Thinking about doing a mod on the exhausts while I have things out, quite like the ‘Q’ car effect but would like a bit more sound.
Just need to modify the head of the trolley jack to make a platform so that I have a steady base to support the unit once I have all the other mounting bolts out.

Round 2, removed the front bolts holding the front of the sub frame off and moved to remove the cross brace at the rear, of course one of the bolts is very tight and its rounded off the head. Plan b remove the bolts holding the rear brace onto the rear suspension.
Finally get the unit out and see that the anti sway bar mount is integral to the lower diff frame;

So I was out scavenging for fire wood yesterday and found some wood that had a load of these fish plates;

So a bit of work with the cut off saw and welder and a few hours work;

Ok slight problem.
I know when I took the diff out the diff flange bolts were facing forward, i.e. head towards the diff and the nuts on the drive shaft side. While removing the diff these fell out. There is no way I can see to get these back into the diff flange so I gave in and mounted them all in the same direction. Head inserted from the prop shaft side.
Anybody see a problem with this?
One of our club members suggested that the Jurid will not last long due to that but I cannot see how the Jurid will know which way they are in as there is a washer between the head/nut.
I surmised that the replacement Jurids had been replaced in-correctly and that they had the thinner section taking the forward motion rather than the thicker area.

So the diff is in and I had 10mm toe on the left rear wheel :(!
The drivers side is nicely centred within the wheel arch so I have a feeling that the lower control arm on the left side is somewhat bent.
Currently in the process of stripping the old diff down and will have to go through the whole procedure again and drop the diff out and insert the pumpkin into my old sub frame OH JOY!!!

Interestingly the new output shaft that I replaced seem to have weathered the abuse of working without the spider gear bearing cup in place very well, no apparent damage so at least I can put those on the shelf for a rainy day.

Dick Maury said,
‘Installing without the carrier bearing race and then driving probably destroyed the axle bearings as they are not designed to handle side loads.’
Dick thinking about this, that large bearing in the out put shaft has to transmit all the side loads into the pumpkin surely? Or are meaning the twisting moment when the C/w moves sideways?

The side axle bearing does carry the side load. On the V8 cars, the side axle assembly also carries the center carrier bearing race. The axle housing screws into the diff housing which sets the lash position of the ring gear. Running without this bearing race in place will place heavy loads on the side axle beading which is not designed to take those loads. Hope this answers your question

I knew it couldn’t be an x300 :wink:

Thanks Dick, I replaced the complete pumpkin into my old subframe, that cured the 10mm toe in on the replacement subframe, I couldn’t detect where the alignment problem came from.

GTJoey, much as you are a fan of the X300 against the X308 they are not immune to problems, My brother had to have his diff replaced in his X300
And mine probably broke because I am not driving it like a nanny, currently due to go on another blast along our back roads with 700+klms of closed roads;

I’m just having fun…
But there are things that don’t exist on the 300 which were on the later car
Enjoy the ride my friend