Rear differential vs. rear bearings

The tires are all the same diameter and circumference. I had them all replaced at Sam’s Club with almost top of the line tires. The car now is at least 7 hours from where I live as the local Subaru dealer had it towed to the nearest Subaru Dealer in Michigan from where the car broke down.

If the dealer drug SIA into this then those people should know what caused this. It’s possible that (no matter if it was a new or used unit) that it could have been installed without anyone considering whether the unit had oil in it or not.

You might ask SIA or that particular dealer whether the unit was dry or not, or had any signs of leakage.
A frozen differential almost always points to no oil and it’s also very easy to diagnose.
With the cover off heated bearings will turn blue in color, the ring and pinion gear will be chewed up, and there will likely be an excess of metal debris in the bottom of the case.

It could be that at this point (since SIA is involved) that they may be trying to work a behind the scenes deal in which SIA will cover this for you as a Good Will warranty and then go back against the dealer for reimbursement. This would kind of put a happy face on it PR wise because the “real cost” of that differntial to SIA would be miles below 1600 dollars and would likely make them look real good to you for being a stand-up company.

Here is some additional information on the failure:

Vehicle is a 1998 Subaru Legacy Outback with 116k miles. All major service has been performed by the dealer.

Dealer replaced the differential at 116k miles with a factory unit. Invoice shows a charge for lube. Presumably if they forgot the lube it wouldn’t have made it 50 miles.

There is no mention on the invoice that rear wheel bearings needed serviceing. The owner always has the dealer complete the recomended services and would have had them replace the rear bearings if they thought it necessary.

After 350 miles, there was under vehicle fire damage around the differential area. The local volunteer fire department extinguished a smoldering fire, presumably the differential oil.

There is no externally visible damage to the rear wheel bearings. Because the differential is locked, the rear wheels won’t turn either, so it is not possible to determine rear wheel bearing condition without further disassembly.

Opened a case with Suburu Customer Service since the dealer that did the repair refuses to take responsiblity for what appears to be a repair failure under warranty.

Subaru asked that we have the dealer where the vehicle is at disassemble the rear end assembly enough to determine what failed and what needs to be repaired, to the extent possible. Probably a $500 effort on a vehicle that is probably totaled due to the fire damage. Too bad since the vehicle is in very nice condition due to having all service done at the dealer.

We’ll see what the dealer finds upon disassembly. I can’t think of any failure mode for the rear wheel bearings on an independent rear wheel vehicle that would cause rapid failure of a new differential. I can see insufficient lube as a possibility, different size tires (which it didn’t have), defective differential, defective installation, or possibly an incorrect ratio (but it wouldn’t drive very well with that…)

From everything I’ve seen in the thread so far, I cannot imagine any way the dealership can escape responsibility. NOTE: I said the dealership, not Subie of America. Their work should be warranteed and I cannot see how the failure of the differential can be seperated from the repair of the differential.

If one wheel bearing were to bind up, you’d feel the drag on the car, and that side of the car would pull. That wheel would be creating a significant load. Besides, the wheel bearing would have fried before the differential died.

I’m sorry, but I don’t see how how the dealership can evade this one.

I’m in agreement with mountainbike. If it was a parts failure on a new differential this could put SOA/SIA on the hook for the money you spent and possible the value of your car.
They would probably argue the point about the car value if declared a total. (quite likely and as it should be)

If it was an installation problem (no gear oil, filler plug left loose or completely out, etc.) then the dealer should be on the hook for it. They too will protest more than likely.
Either scenario means you may have to push the issue.

In my mechanical lifetime I have never seen or heard of a seized wheel bearing. They start off whining or humming, may progress to a rumble and then grinding. In the worst case scenarios they may disentegrate and the car will lose a wheel. There’s advance warning before the really bad stuff starts.

I would make sure that differential has a filler plug in it for a start. Keep us informed. This cause and resolution to this could be pretty interesting. Just offhand, it seems to me that they owe you for a car not just a differential.

It’s not a big deal to weed out the wheel bearings, which are a non-issue in my opinion. All they have to do is disconnect the 2 rear halfshafts from the differential.
They should not have to resort to disassembling half the car to figure this out and that includes the differential. An hour at best in my opinion.

Since the dealer refuses to take responsibility, an autopsy of the rear differential is probably warranted. If the car was totaled due to the fire, the dealer owes the owner fair market value for the car. Blue book value is $7,500.

You sound like a lawyer, so I’m glad she found some professional help.