E70 X5 Rear Differential failure

[Ninja]

Hi

I have an X5 E70 late 2007 just over 106k kilometres on clock and has never been driven off public roads and regularly serviced at BMW dealer.

The rear differential failed today. We took it to our BMW indy after a grinding noise from the rear wheels, the whole unit basically busted and oil started leaking everywhere. Got quoted almost $4,000 (AUD) to replace just the part itself.

Has anyone encoutered this fault with their BMW X5 E70, and should BMW cover these parts as it is a design fault?

Is this a common failure on E70s?

Regards
Leon

[bawareca]

Sorry to hear that.Looks like that is a design fault or something else,but this failure happens regularly.My friend's 08 X5 4.8i just had the same failure few days ago.
$4000 sounds absolutely outrageous.Here is a part # for a rear differential for 08 X5 4.8is Euro,RHD- 33107552530 .It is $2050 (before discounts) brand new here,so you should be able to find a used one and have it shipped for much less than that.

[conedoctor]

Define "failure happens regularly"

Is this a huge common issue we should all be looking for?

[bawareca]

How could I define that?My 87 325is race car diff is still going on with 440whp/400wtq and 255 slick tires.On the other hand I heard for a 4 E70 diff failures last week alone.My friend's 08 4.8i has the diff removed yesterday and the shop owners says that one of the bearing races has moved somehow and there is a complete mess inside.Likely nothing is reusable.

[JCL]

Originally Posted by bawareca

How could I define that?My 87 325is race car diff is still going on with 440whp/400wtq and 255 slick tires.On the other hand I heard for a 4 E70 diff failures last week alone.My friend's 08 4.8i has the diff removed yesterday and the shop owners says that one of the bearing races has moved somehow and there is a complete mess inside.Likely nothing is reusable.

Any potential causal factors?

Tire pressures balanced left/right?
Tire sizes original spec?
Fluids changed out of spec?
Any tire spinning, even on-road (snow or ice)?

There are some web reports (very sparse) of E70 differential failures, but given that in thousands of threads here it has never come up, I would be looking to common factors in those failures. Driver abuse would be the first thing I would look to, unless there was evidence of poor maintenance. If it was a design fault I would expect many more failures than have been reported, and much earlier in the vehicle's life.

[Price]

From what I've read, rear diffs fail mostly on 4.8 and diesel cars due to higher torque, and mostly due to abuse, e.g. hard launches, heavy towing.
Not saying OP did it, just answering "is this a frequent thing?"

[bawareca]

Normal failure rate for the BMW [rear] diffs is close to zero under, let's say 150 k miles.I didnt hear of any E53 diff failures,let alone in this spectacular fashion,self-destruction.That is why hearing of a few E70 diff failures within a week is a pattern.I dont know details,but the diff usually goes noisy,clunky,etc but still the car could move under it's own power.
Regarding hard launches:
-the transfer case will suffer much more than the diffs in such a situation.It is far more fragile than the diffs and will brake much more earlier. 400 lb/ft of torque split between the axles is not enough to break WELL engineered parts.
-I have done many hard launches with stock diffs on my drag days.If you have a wheel hop you brake a tooth.The diff is noisy,sometimes clicking badly,but the car still moves on it's own.

[Ninja]

Thanks for all your reply. Tempted to source a used E70 X5 rear diff, however the majority of these would be around similar age and will probably break soon.

I've decided to take it back to the dealer and have it replaced as they offer 24 months warranty on parts and labour as I'm planning to keep the car for a while. Apparently you can replace a stronger diff, especially you are planning to do a lot of towing and 4WD.

Seriously I'm pretty disappointed at the quality of E70 X5, will try to write a letter to BMW HQ seeking reimbursement for the cost of repair.

[1naztyx5]

had mine fail on 11/2012. it was covered by CPO had 55k miles at the time . also never driven other than public roads, as per SA the RD was destroyed.


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[BMWjason]

There are a few recorded failures, one in particular is on YouTube which was catastrophic, the gear box bearings came apart. The only way to change oil in the rear diff is to suck it out. BMW states the lube is lifetime. What I did on my 4.8 is squirt a tube of LubroMoly antifriction for gears for insurance and to keep it cool and quiet over the long term. Differentials get hot, especially in the South and they do fail over the long term if not cared for, especially with 360 horsepower driving them.