My neighbor also had a hole in his 07 Dmax. It was beyond repair. Truck had 109,000 miles so just out of warranty. He had the fluid changed at 50K and 100K and there was no warning anything was Amis.
I lost a transfer case in my 89 Chevy but can't honestly say what happened. It only had 35,000 miles. When it broke it locked up and sheared the drive shaft off vaulting the trucks rear in the air. Scarry as heck. Luckily I was going under 30 mph.
Chris
What happened with his is it knocked a whole in it and only leaked fluid while he was driving. He ran it til there was not any fluid in it. That seems to be what happens to most of them.