Rear differential fluid temperature

My co-worker's Nissan Titan rear differential has heat sink cooling fins.
You can see the fins from the rear.

Tundra doesn't seem to have a heat sink or fins ... why does Titan have one?

Curious what's the typical rear diff fluid temperature range in Tundra?
does anyone know?

Something new to worry about ...

 

I don’t know the exact temps, but you can touch the housing after driving and it’s not too hot. I’ll test it with an infrared thermometer next time I drive.

 

It’s been awhile but IIRC there were failures because the rear diff would overheat and lose fluid in the earlier Titan models. I think Nissan eventually fixed the issue with the redesigned housing that included those fins. I’ve noticed some other trucks have this design too... but they’re usually the HD models. IDK what the typical range is for a Tundra but I don’t remember reading about any failures here.

 

Just drove about 20 min / 12 miles to work on country roads at 60-65 mph and tested it. I know the housing isn’t the same as the fluid temp, and I’m sure fluid temp is higher than the housing, but it wasn’t overheating. Not sure about the difference with more load. The housing and fill plug were around 100f. I didn’t crawl under it, but from the angle I was at the drain plug was 70f.