Rear diff on 88 RRC knocking

Subject says it all really.

Rear diff (150k of use) has started (today) to make a knocking noise not
unlike a failing CV joint. Starts at about 20 mph and gets louder until
it's drowned out by all the other usual RR noises. At first I thought
(hoped) it was a prop shaft UJ but my bloke has had it up on the lift
and isolated the noise to the diff. Says that the pinion gear carrier
(IIRC) is on the way out.

Recommended course of action please.

[1] Replace diff with px item
[2] Ignore until it goes bang and hope that the failure doesn't damage
the axle case

If [1] is it a DIY job? Genuine manual assumes that the diff is only
removed for overhaul and (seems) not to give any hints about pulling or
refitting drive shafts etc.

TIA

Richard

--
Real email address is RJS at BIGFOOT dot COM

The information contained in this post
may not be published in, or used by

http://www.diyprojects.info

In <[email protected]> Richard wrote:
> Subject says it all really.
>
> Rear diff (150k of use) has started (today) to make a knocking noise
> not unlike a failing CV joint. Starts at about 20 mph and gets
> louder until it's drowned out by all the other usual RR noises. At
> first I thought (hoped) it was a prop shaft UJ but my bloke has had
> it up on the lift and isolated the noise to the diff. Says that the
> pinion gear carrier (IIRC) is on the way out.
>
> Recommended course of action please.
>
> [1] Replace diff with px item
> [2] Ignore until it goes bang and hope that the failure doesn't damage
> the axle case
>
> If [1] is it a DIY job? Genuine manual assumes that the diff is only
> removed for overhaul and (seems) not to give any hints about pulling
> or refitting drive shafts etc.


I'm not sure exactly what he means by pinion gear carrier TBH.

There are a few items that can wear and cause slop in a diff but if it's
the pinion bearings that have gone then they can be replaced quite
easily. To test them take the tension of the propshaft (chock the wheels
and take the handbrake off, gearbox in neutral) you should then be able
to rotate the propshaft slightly. See if there is any up and down
movement in the diff where the propshaft meets it. If there is then
either the pinion bearings need replacing or the drive flange is worn.

If there is movement then take the propshaft off at the diff end and try
moving the drive flange up and down whilst keeping an eye on the nut and
shaft in the middle. If the drive flange is worn then you will get
movement in the flange but the nut and shaft will stay put - the drive
flange can be replaced with the diff in situ and is often misdiagnosed
as a worn pinion bearing. (I have to confess that I once removed a front
diff to replace the pinion bearings only to realise when I had the diff
on the bench that it was the drive flange - spending two hours to do a
10 minute job !)

Internally, the cross shaft that the planetary gears run on can wear an
oval hole in the carrier which requires a new carrier but you'd have to
have removed the diff to be sure of that diagnosis. A knocking or
clicking noise could be anything but normally I'd expect more of a
rumble

Removing a rear diff is a simple enough job. You may have to remove both
wheels though in which case you'll need axle stands. Don;t forget to
chock the wheels - your parking brake won't stop the vehicle moving once
you remove the halfshafts ! Some wheels allow you to remove the half
shafts without removing the wheels but most Range Rover wheels don't. If
you don't have axle stands or feel safer with the wheels on the ground
then remove a wheel, remove the halfshaft and put the wheel back on then
do the same the other side. The manual will have a description for
removing the half shafts but in essence you undo the 5 bolts that hold
the drive flange to the hub and the drive flange, complete with half
shaft, pulls out of the axle. Pull both half shafts out about 6 inches (
or all the way if you have room), disconnect the propshaft (if you only
disconnect the diff end then tie the prop up SECURELY out of the way),
drain the oil from the diff pan (drain plug under the axle), undo the
ring of bolts holding the diff to the axle casing and pull the diff out.
If you've not lifted a diff berore then be aware they are heavy. I
usually lie on my back under the diff and lower it onto my chest then
roll it onto the ground.

cheers

Dave W.
http://www.yorkshireoffroadclub.net/

Dave White wrote:

< a lot of very useful and clear information that I snipped>

>cheers
>
>Dave W.
>http://www.yorkshireoffroadclub.net/
>
>

Thanks Dave,

There is no play in the UJ or the i/p shaft to the diff. With the RR
supported on the lift with all wheels off the ground we were able to get
some monumental knocks from the diff - even louder with the oil filler
plug removed. Seems pretty conclusive that there is something amiss
with the guts of the diff. In fact it got even worse as I drove
gingerly home.

It seems that Paddock have recon units with 6 months warranty for ~
£100. Any views?

I was also wondering if I should remove the rear propshaft for my return
journey to my spanner wielder and drive it to him with the diff locked?

On the other hand I do have four big axle stands and a couple of
hydraulic jacks. The genuine manual says nothing about removing drive
shafts, let alone removing the diff - it assumes that you only want to
overhaul the diff. But from a closer look at the spares book what you
say about pulling the drive shafts out makes more sense to me. Is it
really that simple? Just pull the shafts, disconnect the prop, unbolt
the diff and discard, refit the new diff with a new gasket (joint
washer?) and refit the shafts. No awkward setting up of backlash and
clearances? What about getting the drive shafts back into the differential?

Thanks Richard


--
Real email address is RJS at BIGFOOT dot COM

The information contained in this post
may not be published in, or used by

http://www.diyprojects.info

In message <[email protected]>, Dave White
<[email protected]> writes
>If you've not lifted a diff berore then be aware they are heavy. I
>usually lie on my back under the diff and lower it onto my chest then
>roll it onto the ground.
Then what do you do with the ep90 that drains down your arm and works
it's way around the neck of your overalls ...

--
AndyG

AJG wrote:

> In message <[email protected]>, Dave White
> <[email protected]> writes
>
>> If you've not lifted a diff berore then be aware they are heavy. I
>> usually lie on my back under the diff and lower it onto my chest then
>> roll it onto the ground.
>
> Then what do you do with the ep90 that drains down your arm and works
> it's way around the neck of your overalls ...
>
Treat it as free a waterproofing or, if you wear them for welding, or as
an accelerant?

Richard ;-)

--
Real email address is RJS at BIGFOOT dot COM

The information contained in this post
may not be published in, or used by

http://www.diyprojects.info

"AJG" <[email protected]> wrote in message
news:[email protected]...
> In message <[email protected]>, Dave White
> <[email protected]> writes
> >If you've not lifted a diff berore then be aware they are heavy. I
> >usually lie on my back under the diff and lower it onto my chest then
> >roll it onto the ground.
> Then what do you do with the ep90 that drains down your arm and works
> it's way around the neck of your overalls ...

and smells like cat wee

In <[email protected]> AJG wrote:
> In message <[email protected]>, Dave White
> <[email protected]> writes
>>If you've not lifted a diff berore then be aware they are heavy. I
>>usually lie on my back under the diff and lower it onto my chest then
>>roll it onto the ground.
> Then what do you do with the ep90 that drains down your arm and works
> it's way around the neck of your overalls ...

I usually take it as a given that crawling under a Land Rover is always
going to lead to ep90 supplying a "natural" Land Rover water resistance
and insulation to your overalls

cheers

Dave W.
http://www.yorkshireoffroadclub.net/

In <[email protected]> Richard Savage wrote:
> There is no play in the UJ or the i/p shaft to the diff. With the RR
> supported on the lift with all wheels off the ground we were able to
> get some monumental knocks from the diff - even louder with the oil
> filler plug removed. Seems pretty conclusive that there is something
> amiss with the guts of the diff. In fact it got even worse as I
> drove gingerly home.
>
> It seems that Paddock have recon units with 6 months warranty for ~
> £100. Any views?

Doesn't sound like too bad a price, second hand units seem to go for
around 40 to 50 quid normally but if these have been reconditioned
properly, which I would guess should include renewing and reshimming the
pinion bearings and replacing the carrier bearings then that doesn't
sound too bad.

> I was also wondering if I should remove the rear propshaft for my
> return journey to my spanner wielder and drive it to him with the diff
> locked?

As long as you have the drive shafts in place the diff is still going to
be turning so removing the prop shaft probably wouldn't make any
difference. If you were to replace the rear drive shafts with two spare
front ones (they are about 8 inches long) then it would be worth doing.
I carry two front drive shafts in my competition motor for that very
purpose.

> On the other hand I do have four big axle stands and a couple of
> hydraulic jacks. The genuine manual says nothing about removing drive
> shafts, let alone removing the diff - it assumes that you only want to
> overhaul the diff. But from a closer look at the spares book what you
> say about pulling the drive shafts out makes more sense to me. Is it
> really that simple? Just pull the shafts, disconnect the prop, unbolt
> the diff and discard, refit the new diff with a new gasket (joint
> washer?) and refit the shafts. No awkward setting up of backlash and
> clearances? What about getting the drive shafts back into the
> differential?

Yes, it is that simple... normally. Sometimes you get small burrs on the
end of the drive shafts that can make it difficult to get them to slide
out but most of the time they pull out without any real effort. You only
need to set up the backlash etc.. when you take the diff itself apart -
with a recon unit it will already be set up.

Getting the drive shafts back in isn't too bad, you just slide it in
until it stops, pull it back slightly, manipulate the drive flange to
lift the far end of the drive shaft and rotate it until it engages then
push it home. It's easier to do than it is to explain it !

You'll need gaskets and sealant for the diff and the two drive flanges.

If you go for the recon one you can always rebuild the old one at your
leisure. They really aren't difficult to set up, all this talk of back
lash and the "there be dragons here" when it comes to diffs is a bit
overkill. Once you actually get the thing on the bench you'll find it's
pretty obvious how they go together.

cheers

Dave W.
http://www.yorkshireoffroadclub.net/

Dave White wrote:

>Getting the drive shafts back in isn't too bad, you just slide it in
>until it stops, pull it back slightly, manipulate the drive flange to
>lift the far end of the drive shaft and rotate it until it engages then
>push it home. It's easier to do than it is to explain it !
>
>
>cheers
>
>Dave W.
>http://www.yorkshireoffroadclub.net/
>
>
Well, you've convinced me! I'm looking forward to the
easier-to-do-than-explain drive shaft fitting tho'. When I replaced the
propshaft on my bike (1150GS Beemer) it was an absolute nightmare of
wiggling with screwdrivers to get the bloody splines lined up at the
gearbox end. Still, at least I won't have a pair of uncooperative UJs
to make life interesting.

Cheers

Richard

--
Real email address is RJS at BIGFOOT dot COM

The information contained in this post
may not be published in, or used by

http://www.diyprojects.info

"Richard Savage" <[email protected]> wrote in message
news:[email protected]...
>
>
> Dave White wrote:
>
> < a lot of very useful and clear information that I snipped>
>
> >cheers
> >
> >Dave W.
> >http://www.yorkshireoffroadclub.net/
> >
> >
>
> Thanks Dave,
>
> There is no play in the UJ or the i/p shaft to the diff. With the RR
> supported on the lift with all wheels off the ground we were able to get
> some monumental knocks from the diff - even louder with the oil filler
> plug removed. Seems pretty conclusive that there is something amiss
> with the guts of the diff. In fact it got even worse as I drove
> gingerly home.
>
> It seems that Paddock have recon units with 6 months warranty for ~
> £100. Any views?
>
> I was also wondering if I should remove the rear propshaft for my return
> journey to my spanner wielder and drive it to him with the diff locked?
>
> On the other hand I do have four big axle stands and a couple of
> hydraulic jacks. The genuine manual says nothing about removing drive
> shafts, let alone removing the diff - it assumes that you only want to
> overhaul the diff. But from a closer look at the spares book what you
> say about pulling the drive shafts out makes more sense to me. Is it
> really that simple? Just pull the shafts, disconnect the prop, unbolt
> the diff and discard, refit the new diff with a new gasket (joint
> washer?) and refit the shafts. No awkward setting up of backlash and
> clearances? What about getting the drive shafts back into the
differential?
>
> Thanks Richard


Richard,

Don't worry I'm not ignoring you!. I tried to reply to your e mail you sent
re Holey chassis and it got bounced back twice. Chassis is still holey and
the MOT looms ever nearer.........

Dom J