Hi, Scotty! Thank you so much for everything you do! I saw a lot of videos about vehicle maintenance on your YouTube channel and know that is better to replace transmission oil (not flushing) if mileage is not too big.

I have a BMW Z4 E85, 2004, 2.5 liters 105000 mileage, engine m54, automatic transmission ZF (hope so).
I don’t have any information about previous maintenance regarding transmission and differential oils.
However, I have replaced spark plugs recently and they were original old BMW. Therefore I believe there’s been little to no maintenance by previous owners.

Basically, I have two questions:

1. Do you think I should change transmission oil or it is better not to touch it at all?
2. What about differential oil - given the mileage and age - should I change it?

The reason I have these questions is because the repair shop guys are saying there’s no need to replace oils unless there’s a leakage; the claim the oils have a lifespan of a car. In my case there’re indeed no leaks/ issues, but I used to (and it was recommended) replace oils at my previous cars (they were much fresher cars though, 2012-2014).

Thank you in advance!