rambling rollie wrote:

Greetings!

At what point does one do this bearing replacement?
At the "humming" phase? (i almost believe "humming" from FL2 rear diffs is standard)...
Or do you wait until it starts whining? (a significantly higher pitched version of humming).
Or when it starts making "whirring" sounds?
Obviously once it starts making grinding noises it's probably overdue...

I ask because mine has been humming for months (maybe even a year, i cannot remember)....

Before it seizes up, which mine did while driving at 40 MPH, just before Christmas. Although to be fair, mine had no oil in it, so I'm surprised it lasted as long as it did. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, the daily driver.
1972 Hillman Avenger GT, the project.

MRRover75 wrote:

Hi,

I have given up speculating the main reason why these pinion bearings fail. Only thing I know, is that the 9 ones I have rebuilt, have worked superb and I have no reports back from anyone that they have failed. I guess these has not been on the road long enough to build a greater mileage, but some should have failed allready if something was assembled wrong. I have only used Timken and SKF bearings. Mine has now done aprox. 50000kilometres after assembly, so probably as good as they was when new. Early diffs (-07-09) seem to hold 200000km+ before the pinion bearing fails. later ones more early for some reason but some mentioned that cheap bearing copies from China was used there !?!

Regarding lubrication, there is two oil channels to the outer pinion bearing in the casting. One lower probably below the oil level, and one higher up, probably for ventilation of some kind. Lack of frequent oil changes is probably contributing to a reduced lifetime...


I also feel the pre-load on the bearing seems a bit high, but I have not gambled on reducing this on my rebuilds. Just sticking to the OEM procedure when tightening up. Only thing is that I throw away the torque wrench. A lot more torque is needed to start compressing the collapsible spacer than the specified 250Nm.

Mine actually seized solid while doing 40 MPH just before Christmas, so my diff is now most likely scrap. The cause for this was actually due to there being nothing more than a few drops of oil in it.

I've studied the diff design, and come to the conclusion that these continual failures are probably down to a combination of factors.

The pre-load is I believe too high, for the size of the front bearing used. High pre-load, will result in delamination of the case hardening, which is what appears to happen on these bearings.

This ailment also effects the Discovery 3 front diff, which again is due to excessive pre-load, coupled with too small a bearing for the task. I've rebuilt several D3 front diffs, all suffering the same delamination of the case hardening, and all had excessive pre-load when reassembled using the factory shims, but thankfully its easy corrected before final assembly.

Lubrication, or lack of. Looking at the diff design, the oil feed to the front bearing is poor at best.
All differentials use oil for lubrication and cooling. A standard diff is designed so that oil is freely thrown around all moving parts by centrifugal action of the crown wheel. Almost all differential cases are designed to channel a large proportion of this oil directly to the outer most pinion bearing. See the size of the cast in oil gallery hump in this Freelander 1 rear diff, where the oil travels to the pinion bearing in large quantities.

The pinion is spinning fast by comparison to the crown wheel, so needs a good supply of fresh oil to replace that, oil which is displaced by the bearing rollers.

This is where the flat design of the Freelander 2 diff is lacking, as there's insufficient height for a large oil gallery to capture this centrifuged oil, limiting the oil supply to the front bearing. If the oil supply to a bearing is compromised, then the bearing will run with less than an ideal amount of lubrication, which then causes it wear faster and to run hot. This lack of lubrication, coupled with the higher than I feel is ideal pre-load, is my best guess as to the early and frequent demise of these bearings. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, the daily driver.
1972 Hillman Avenger GT, the project.

Hi all,

Just an update and a great excuse to bump this thread

Luckily, the diff I rebuilt in the beginning of this thread is still running smoothly and in daily use. Many miles has been covered since then..... (knock on wood)....

I get contacted very randomly from people that have heard the rumors, and they need their diffs rebuilt.
no. #16 just went out the door and no.#17 is now during assembly at the workbench:



Hope all lasts

Some quick questions for MRRover75 (or anyone else who knows the answer really)...

I've just purchased a recon diff from Bell Engineering but want to add the drain plug modification...however I want to clean out any swarf which finds its way into the housing, which means removing the LH cover.

Does anyone know:
i. Can the diff cover gasket be reused, and if not, what is the part number?
ii. What is the torque for the diff cover bolts?
iii. Loctite or not on the bolts?

Thanks
Andrew

Scratch that...did a bit'o'googling and found the answers to my own questions...

i. Differential case seal = LR030846
ii. x7 Differential case bolts tightened to 29Nm
iii. Not specced in LR workshop manual (but a bit of blue wouldn't go amiss)

👍

glad you found the answers Jules

An interesting thread, and many thanks for the photo's that show all. I had one done at our local specialist. He said that the bearing fitted is under-rated and Landrover later fitted a larger nose bearing. I have had two diffs rebuilt, so far, at different specialists. I would always use EP90 Hypoid gear oil in a differential. I used to make tooling for the old Rover Company, and diff. pinion bearings were always torqued at 120 lb ft., with a four thou preload. the spacer was ground to suit. The nut was staked, to lock it. Three foot of bar on the socket, and lean all one's weight on it was usually good enough. ( nobody was over eleven stones in those days). I still have a few of the setting blocks in the toolbox. Engineers blue was used to check the gear alignment. The gears, in use, wipe across the contact area, which is why a high shear oil is used. Commercial vehicles use higher spec. oils for longer life. We have many local Lorry Companies with million mile plus vehicles around here, and money is better spent in prevention, rather than constant repairs. It is a pity Landrover has cur so many corners in recent years. Having refurbished some of their tooling in the Nineties, quality improved for a while, until the Bean Counters got too strong.

Good someone has the correct answers allready

I would like to add, that there should be no problem to reuse the differential case seal as yours is fresh and clean. An O-ring has no problem to tolerate that. I use to add a very thin line of Loctite flange sealant to the flange on mine, just as an extra seal. Many of these have some pitting/corrosion close to where the O-ring seals, so I do this in case the O-ring does not seal properly. Probably not needed to yours I guess.

Add some blue loctite to the bolts on refitting

Unbeliever wrote:

Scratch that...did a bit'o'googling and found the answers to my own questions...

i. Differential case seal = LR030846
ii. x7 Differential case bolts tightened to 29Nm
iii. Not specced in LR workshop manual (but a bit of blue wouldn't go amiss)

👍

Many thanks for the clarification MRRover75...much appreciated 👍