The 'Lifetime' fluids are 60,000miles, which is the same as the warranty, so they're right on that score.

At the distance yours has done a fluid change has a greater possibility of accelerating a failure because cleaning the crud out changes the tolerances and you could get a failure. We're talking 'probability scales' here on the statistical approach.

A warranty or mechanical breakdown is the only kind of insurance that covers this.

BMW don't touch transmissions, they replace failed units with remanufactured ones - for a lot more money. Approx $16,000AUS (£10,000GBP), to change a complete ZF 6sp and Mechatronics Unit. $5,000 for a rebuild sounds a little high, but then Melbourne is expensive.

A stripdown and check can be a proactive piece of preventative maintenance and cheaper than a complete rebuild, but could also be seen as OTT.

There really is no hard and fast rule set covering this, it has to be done based on the balance of probabilities and what you can (a) afford and (b) be comfortable with doing.

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