hi all
I just recently bought used mazda Cx9 2011 with 236000 kms (146000 miles). After buying i realized common issues water pump and ptu issues and planned to do maintenance before they get failed. To my surprise here in this part of world U.A.E there is no such TSbs or recalls so when i checked service of car with my local mazda dealer they refused to change PTU fluid and also the transmission fluid. I told them about Failures of PTU on forums and he laughed. So i decide to carry on my local garage service. For transmission i did drain and refills myself 3 times with toyota T-IV and fluid came out was nasty black but my transmission survived.
For PTU i took it to my local garage i know him from many years he agreed to change fluid and i helped him with You Tube videos
how to replace PTU fluid. We unplugged the bolt on PTU and when we tried to suck out fluid nothing come out but just 100ml grease
. Mechanic was shocked to see that and he suggested to just keep pumping new fluid in so old grease will come out which was a tough task without drain bolt. Filling with Motorcraft 75w140 mechanic suggested me to drive the car for few days so old sludge/grease will dissolve in new fluid and he will do drain refill again but he warned that PTU might get whine noise after these fluid changes ( I already have slight low whine above 60 kmh)
I drove the car and found no change in sound better or worst. The magnet bolt was full of metal sludge no shavings, mind we have temperatures above 50C in summer lasting for 6 months or more and im surprised how car survived in such harsh conditions and temperature for 9 years with 146000 miles.