Transmission warmer "puck"

Does anyone know exactly what this puck shaped warmer is like internally? Is it just a small coil for the heat exchange to occur or what? Just wondering if it has potential to eventually leak and destroy the transmission with coolant. I mean if the right conditions existed such as various components becoming stuck closed or clogged and pressure builds who knows what might blow apart. Had a Mercury product once and it blew apart in many components. Thermostat or not, rigid piping, heater valve, thermostat housing, and a few radiators too. Damn thing was a real headache until I bought a lower pressure cap. Still had some problems even after that.

 

I wouldn’t worry about it, pretty sure the engineers thought of it already.

 

The post below by @TundraTRD11 comes the closest I've seen to showing the internal configuration of the warmer.

https://www.tundras.com/threads/transmission-cooler-or-not-thread.76250/page-11#post-1961822

It is not a simple coil inside a can. The cross-section drawing above appears to show a densely-packed internal heat exchanger of stacked plates. I suspected something other than a simple coil when I saw a warmer schematic showing multiple parallel ATF passes inside the can.

The diagram in the post above is for the A750 transmission warmer (4.7L), but that is probably not important since all Toyota's warmers of this style will be of the same design pattern. Can you have a failure of the stacked plate exchanger inside the can, and have cross-contamination of the ATF with coolant? Absolutely. But, it won't be pressure that causes the failure; a more likely cause of failure will be corrosion or fatique cracking at exchanger connections. Hopefully, the heat exchanger inside the can is made out of stainless steel.