E70 X5 Rear Differential failure

[Ninja]

Ours is a 3.0d pre-LCI, basically the rear diff just went busted completely. It was not driveable as the rear wheels would lock up without the diff.

No apparent symptoms before it failed, the diff just snapped out of the blue. It was like a ticking bomb waiting to explode.

[daymo69]

I've got the same problem. Purchased a BMW Premium Selection Vehicle from BMW Melbourne, and have had a string of problems with the car, culminating in the diff packing it in at 100k.

Repairs costs have varied from $4700 at Euroserv Killara (Sydney North Shore) and $8000 at BMW North Shore. Wait is three weeks for part which needs to be shipped from Germany. They have run out of these parts in AU, which would point to the problem being more common than an aberration.

Symptoms in my case were jerking (as if you were driving a manual and didn't have enough revs before releasing the clutch) when accelerating from a standing start. Gradually got worse to the point where it was making a loud clunk, then grind, then the whole thing stopped.

[Ninja]

Unbelieveable..wonder how many E70s owners had a failed rear diff? It appears this is a common issue once it has reached the 100,000km mark.

Yes, the part itself is around $3,800AUD plus labour. $8k seems a bit excessive!! BMW Aust dealers don't normally stock any diff as it is not suppose to break and requires a special order via freight due to its sheer weight and size.

[JCL]

Before deciding that all E70 diffs are at risk of failure, we should try and determine what these failures have in common.

In Ninja's case, the vehicle is a 2007 3.0d. The part number for the diff was changed up in 2009. The new diff is also used in the four cylinder F25 X3, nowhere else. I think it is fair to say that it is smaller and lighter than other E70 diffs, but I don't know the design rating.

The 3.0sd (higher hp), the 35i, the 35d, and the 48 all use different differentials according to the parts book.

For some non-North American models, there was also an optional differential for towing. Same ratios, different part numbers, increased tow rating. That applied to the 2007 3.0d. So, that is another suggestion that the standard 3.0d diff is not as strong as we all might like it to be. For the 3.0d specifically, the optional (towing) diff is the same part number as is used in the 3.0sd and the 35d, among others. For the 4.8i, there is an optional diff for increased towing capacity outside North America as well. Same ratios, so to my simple mind it comes down to strength (duty cycle) and heat management differences.

I would also be interested in whether any of the vehicles with a failed diff had any tuning done, particularly the diesels that are relatively easy to tune. Not to blame the tuning, but to try and determine whether the failure is more likely related to load, or something else.

[hs2k02]

Hi all,
In my opinion the Diff failure issue is not limited to a particular model or part number, it appears that diff failure is common (some may disagree) in some BMW cars built between 2007-2009. Most diff part numbers in that period are marked as superseded in the BMW inventory. Whether it is a poor metal composition or bad design, the problem is there.
As far as my car goes, I don't plan to replace it just because of the diff failing. There is a lot to like in BMWs.

[Ninja]

The majority of E70s owners wouldn't have tuned or trashed their cars given it is a 4WD and family oriented vehicle, unlike high performance BMWs like a ///M3 where the owners might trash it around the track with launch control, high speed cornering etc.

Generally a typical rear diff shouldn't break under normal use, we are talking about a 7-10 yrs old car. Once we have established the number of affected pre-LCI E70s, perhaps it is time for BMW to consider a recall on the faulty rear diff.

[JCL]

Might be different in Australia, but in North America recalls are for safety and emissions reasons, not for parts that don't meet owner's life expectations.

As for part numbers being changed up, it can be for any number of reasons, including simply a supplier change. It isn't an indication that there is necessarily a design or manufacturing problem. Do we know what the part number change up signified?

I agree that a differential shouldn't break under normal use. The existence of a stronger diff for certain models, however, suggests that the standard diff may not have had as much safety margin as other models.

[hs2k02]

In some cases it would be a personal safety issue. With mine, while taking off from a stop sign, the car moved onto the road before diff failure and total loss of mobility.

[ard]

Originally Posted by Ninja

Generally a typical rear diff shouldn't break under normal use, we are talking about a 7-10 yrs old car. Once we have established the number of affected pre-LCI E70s, perhaps it is time for BMW to consider a recall on the faulty rear diff.

Originally Posted by JCL

Might be different in Australia, but in North America recalls are for safety and emissions reasons, not for parts that don't meet owner's life expectations..

Spot on.

Engineering analysis must show that a failure rate has been demonstrated above some threshold, AND that if the failure were to recur it would likely result in a safety issue to occupants or others on the road.

Originally Posted by hs2k02

In some cases it would be a personal safety issue. With mine, while taking off from a stop sign, the car moved onto the road before diff failure and total loss of mobility.

That MAY be construed to be a safety defect that would lead to a recall.



As we see with the GM news recently, car manufacturers fight TOOTH AND NAIL to avoid recalls. You'll need more than a group letter.

Like logging complaints with governmental agencies to start. And rememnber, the issue is '...and it led to a dangerous situation due to _______'. Griping about how much it costs, or that other mfgs dont have failing diffs is NOT a good justification for a recall

[daymo69]

It would seem that the best way to approach a potential recall action would be by positioning the fault as a potential safety issue. The car pretty much stops dead after diff failure, presenting a whole raft of potential safety issues.