[Milanomike]

On my 2008, the TCM acted somewhat intermittently, but it never worked for more than 10 or 15 minutes before going into limp mode. If I cleared the codes, they would come back in less than 15 minutes of driving. What codes is your car throwing. Did dealer test an put old TCM back or a new TCM, this is not clear from your post.

 

[Milanomike]

I read that also, and thought about doing it, but for now did not Mounting to the brake lines at firewall is doable, but seemed like a possible vibration issue to me. I thought it might replace one problem with another. Also, heat from the exhaust may get there, who knows. Transmission oil can certainly get to 225 F - 250 F, not sure how hot the trans case gets 200+ F is too hot for electronics.

Also, I think the TCM unit itself is kind of a crappy design in the way it is sealed. It has the PCB covered with only a thin film of some soft sealant that is sticky which will attract dirt and faces the trans. A thicker non-heat conducting sealant would probably be better and maybe Mazda could improve the mounting location or the unit. My guess is we are stuck with a crappy design.

 

[Milanomike]

Best idea I thought I had was to mount it in original location, but put in heat resistant spacers, neoprene or something ,but couldn't find anything handy at HD or anywhere. This would prevent heat from soaking into the aluminum casing and therefore the stupid board. If you put on brake lines, I would put something like 3 or 5 mm thick neoprene sheet under it to dampen vibes.