My 2017 CX-5 Grand Touring AWD has about 42K miles. I recently had an oil change and the Mazda service advisor recommended only the brake fluid and coolant flushed at 45K. I was considering having the dealership also change the transmission and rear differential fluids. My reasoning has to do with the powertrain warranty. I've heard of vehicles having transmission issues after having the fluid changed. If I wait until 60K to have the transmission fluid changed I'll be out of powertrain warranty. Having the transmission serviced now will give me a solid year of warranty (bought CX-5 new 4 years ago) and 15K miles to make sure the transmission will handle the fluid change without a problem.
Any advice would be greatly appreciated.

 

Coolant is long-life, schedule change is 10yrs or 120,000 miles.
Brake fluid is scheduled for change very two years.
If you plan to keep the vehicle long term, a trans flush is a good investment.

 

In much the same boat, with my 2016 CX-5 GT AWD. Purchased the one-owner car at 79Kmi. A couple thousand miles later, I just had the transmission and differential oil replaced (at a decent nearby "transmission / full-service" shop not Mazda). Shifts feel a bit smoother, and the shift points make a tad less noise. Mazda's suggestion was: don't need to replace the gear oil in those. I've always done it at the 30-40Kmi mark, on prior vehicles. Just did it at ~83Kmi on this CX-5. I'm all but certain the prior owner didn't touch the fluids there, though my transm. tech indicated the fluid looked "good" to him ... only mildly dirty from expected wear on the clutch materials, no stray metal particles, good viscosity and smoothness, etc.

I'd certainly do the brake fluid flush/bleed every two years, and the transm/diff gear oil every ~40-50Kmi or sooner. Might only feel like it's a "peace of mind" thing, but it'll help those components last longer and perform better.

 

Thanks for the recommendations! Now I'm trying to decide if I want the Mazda dealership to do the work or go with a reputable shop that uses BG products. Any advice?

 

For better price and possibly better trained people go to an independent shop that has the ASE sign and staffs them with current certification.
Keep the records of all service work performed both from the a dealership as well independent shops. In USA we have The Magnuson-Moss Warranty Law so you will completely for the remainder of your MAZDA warranty even if you use independent shops.