Please, your opinions as always are much appreciated:

Vehicle: 2004 Defender 110, Old man Emu heavy/medium duty springs resulting in approximately 2” of lift with 31” tires on alloys.

2 Years ago:

Problem:
. Vehicle lurching/ bunny hopping during over run in low gears.
. Loud metallic rattle when foot is off of the accelerator pedal and vehicle is coasting.
. Terrible backlash between gear changes and when lifting foot of accelerator suddenly
.Rough/notchy gear changes from 1st through 3rd (at low speeds).

Apparent root cause:
Snapped center pin in front diffrential. Two resulting pieces of broken pin caused pin holes in carrier to be elongated and planetary gears to be eaten up.

Resolution:
Replaced front diff with one off of a disco. Donor diff condition was in excellent condition with no backlash. Vehicle felt like a brand new defender. Smooth gear changes, no bunny hopping and quiet!

2 Months ago:

Bunny hopping, notchy gear changes and terrible backlash have all gradually returned accompanied by wandering steering.

Removed front diff to inspect and come face to face with a diff that is almost identical to the first one I removed almost 2 years ago.

Snapped shaft, damaged planetary gears, pinion gear and crownwheel.

I replaced the diff once again with another from a donor 110. I checked the donated diff while it was still on the donor vehicle by turn the diff flange and got almost zero backlash between the flange and the half shafts. Oil on donor vehicle was clean with zero metal fragments.

Driving the last 4 weeks or so has once again become a pleasure.

My vehicle is never taken off-road, I am defintely not an aggressive driver and the drive train is keep in pretty good shape. The correct oil is used and the levels are checked regularly and oil replaced every 6 months.

Present time:
Today while crawling through a supermarket parking lot in 2nd gear the 110 started to lurch back and forth and only stopped when I engaged the clutch. This is a very familiar behavoir.

This leads me to ask these questions:

Is the recently installed diff on the way out already??

Why would I experience these failures of the front diff??

What could cause the center pin to fracture so easily with normal everyday road driving??

Are these 2 pin diffs that weak??
My long term goal is to purchase an ATB diff carrier from Ashcroft Transmissions as my confidence in the Rover 2-pin diffs is at an all time low.

Please, what am I missing??

Have you looked at your CV couplings on the front axle?

its possible your putting in worn diffs and as such wont last long

is front prop angle to aggressive and prop not compressing enough so has to put excessive pressure on pinion causing crown wheel to be under excessive lateral force thus buggering up diff

GATSO said:

is front prop angle to aggressive and prop not compressing enough so has to put excessive pressure on pinion causing crown wheel to be under excessive lateral force thus buggering up diff

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I had that with my disco. For some reason after 2" lift, it appeared to be too long. Had to change it for a V8 front prop, which is slightly shorter.

GATSO said:

is front prop angle to aggressive and prop not compressing enough so has to put excessive pressure on pinion causing crown wheel to be under excessive lateral force thus buggering up diff

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To be totally honest I thought about this but i dismissed it because the angle of the front diff is not that steep. I believe that the lift is around 1"to 1.5". It is bugging me now that you thought about it as well.

Oldseadog said:

Have you looked at your CV couplings on the front axle?

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What is your train of thought in relation to this?

LeftFoot said:

What is your train of thought in relation to this?

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Train of thought is that, if the balls in the CV joint are able to jump around in their 'sockets' when taking up drive or when they are running out of gear, it may be possible that they 'clunk about a bit' or even possibly jam up for a nanosecond or two, causing damage to your diff gears and shafts, especially if you have accidentally had the diff lock engaged and wound the diffs up.

Jack up your front end and see how much backlash and play you have at the wheels.

That might give you some indication, as the steering would also be affected.

Please let us know how you get on.

is the slider working fine in your front prop. Mine had seized and it was giving me all kinds of problems

It ain't in difflock is it?

I would not fit a front ATB without a rear you'll end up with awful handling. Get the diff pegged instead, it should stop it from breaking in the way mentioned.

Also why do you have a lift and giant tyres if you never go off road?

There is a possibility that the diffs you have fitted where all on there way out and the larger tyres have sped up the rate of failure.

The Mad Hat Man said:

It ain't in difflock is it?

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No sir it is not.

bankz5152 said:

I would not fit a front ATB without a rear you'll end up with awful handling. Get the diff pegged instead, it should stop it from breaking in the way mentioned.

Also why do you have a lift and giant tyres if you never go off road?

There is a possibility that the diffs you have fitted where all on there way out and the larger tyres have sped up the rate of failure.

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Why would a front ATB coupled with a standard rear diff cause awful handling? Wouldn't the ATB at the front help keep the tracking in check particularly during acceleration and cornering?

Plus, the tyres are 265/75R16s, not exactly "giant" in my opinion. I do accept your point on the diffs being on the way out. James Martin made that point earlier.

Just not the done thing, its an LSD remember so it will lock up and put extra strain on the weaker front shafts meaning you could end up with breakages else where.

So have the next front diff pegged and shouldnt have an issue, much cheaper than an LSD aswell.

Those tyres arnt that big then! Still seems like its kitted out for offroading and you do the school run in it... Considering you dont do any off roading an £800 front diff will do nothing for you but dent your wallet. Not trying to be a dick, just being realistic.

If it is a "proper" lift it could also be causing prop issues, as mentioned above, which can translate into diff issues.