[PFederighi]

Getting close to 7k and so far so good on the '22 awd turbo.

What kind of driving are you doing that would cause this type of failure? Would you say that you were subjecting the drivetrain to any type of 'extreme' driving condition(s)? Did the failure occur when cold or after a long spirited drive, etc?

Sounds like your 3 is basically a commuter vehicle that you have to step on the gas every once in a while to merge.

Maybe substituting whatever oil mazda is putting in there for a 'higher quality' differential oil manufacturer and / or changing the weight, adding 'friction modifier' (if applicable) might provide some extra protection and peace of mind.

 

[Mazdafan74]

Sounds good but without lsd clutches in the rear friction modifier won’t be of any benefit.

 

[perseus]

Sounds good but without lsd clutches in the rear friction modifier won’t be of any benefit.

Wonder if it'll approach recall territory. Didn't someone mention that their factory diff that failed appeared to be missing a spacer? Maybe missing spacer + built to mins = recipe for failure.

 

[polird]

Perhaps this has some relevance to the failures? Came across it while researching my rear end vibration issue.

Cracked Rear Differential SA-033/21
MC-10194782-0001.pdf (nhtsa.gov)

 

[Mazdafan74]

Cool that confirms the rear diff being from the parts bin and knowing some of the other vehicles makes 200,000 plus before it’s no longer economical to repair, I’m happy with my choice but the cracked diff may be a supplier issue.

 

[polird]

Cool that confirms the rear diff being from the parts bin and knowing some of the other vehicles makes 200,000 plus before it’s no longer economical to repair, I’m happy with my choice but the cracked diff may be a supplier issue.

The SA reads like the failure is caused by excessive torque on the coupling, especially from "loading up" the driveline by starting aggressively off the parking brake. Presumably this is the same as "brake launching" intentionally, which I know some people like to do. Occasionally I'll let the parking brake auto-release when coming out of a parking spot, but I never launch my car with the brakes. But yeah it seems like a parts bin components with minimal safety factor if the stock torque can blow the differential right out of the dealer lot.

 

[Mazdafan74]

How long has the electric parking brake been a thing?

 

[arathol]

How long has the electric parking brake been a thing?

2017....

 

[perseus]

2017....

"This concern is caused when the sliding bearing (1) in the coupling (2) is seized and causes the coupling component to fit loosely. The pinion shaft head (3) then contacts the differential case and causes a crack."

Prior to causing a crack, do you think that a sliding bearing that seizes is something that might be causing my driveway and hard turn knock that normally only occurs during the first drive of the day?

This TSB seems to fit with the earlier steep driveway case failure and the possible increased occurrence in the higher torque turbos...