Rear Diff Failure, 2018 528i xdrive

[JXW]

156,000 miles. Diagnose rear diff failure. Hard vibration at 50mph very sudden symptom.

At 90k had fluid changed from OEM original to BG. I had some noise before this fluid exchange. Was under CPO should have pushed to see root cause then.

I drive highway daily, 70 80mph.
First time I have had rear diff fail on any car or truck.

Replaced with used part, $2200. It has one year warranty.

 

[TomYoung]

What did the original fluid look like when it came out? Why would you choose a BG product over OEM?

Agree that under warranty, it would have been good to chase down the noise. What are you using in the new (to you) unit?

 

[Marcozi]

How much GL5 was drained from the diff? Did the diff have any leaks?

 

[atikovi]

At 90k had fluid changed from OEM original to BG. I had some noise before this fluid exchange.

Sounds like after 66,000 miles of noise it finally let go. Who changed the fluid to BG? Not BMW I assume. Why wasn't the noise addressed under CPO?

 

[2heeldrive]

Just had the rear diff replaced (under warranty) on my 2019 X5 at 40,000 miles. The pinion seal was leaking and the dealer screwed up the repair.

BMW has very specific oil requirements these days. I would not use anything other than OEM fluids in the drive-train.

 

[BMWTurboDzl]

How much GL5 was drained from the diff? Did the diff have any leaks?

I wonder if it was leaking. Rear diff failure on a BMW is extremely rare.

 

[JXW]

What did the original fluid look like when it came out? Why would you choose a BG product over OEM?

Agree that under warranty, it would have been good to chase down the noise. What are you using in the new (to you) unit?

Dealer sold and used BG fluid to exchange in rear Diff. They did not give me any feedback on OEM fluid when it was removed or if it was low either.

 

[JXW]

I wonder if it was leaking. Rear diff failure on a BMW is extremely rare.

Pinion seal or flange was replaced 1K miles ago at Indy. I asked them to top off fluid and they did but said it was "not that low".

 

[BMW Dom]

My dad's 328i xdrive had a bad front differential.

 

[2heeldrive]

Pinion seal or flange was replaced 1K miles ago at Indy. I asked them to top off fluid and they did but said it was "not that low".

And now for the rest of the story. A repair on the diff... and a thousand miles later it craters. What a coincidence. I think I would be shopping around for a new mechanic.