Xterra transmission and timing chain problems

At 69,000 miles the transmission on my 2007 Nissan Xterra failed AND the timing belt adjusters wore out. Nissan covered the cost of a new transmission only because they were forced to by a class-action lawsuit over this issue. It’s caused by a faulty tranny cooler that’s built into the radiator – engine coolant gets into the transmission fluid, which destroys the transmission. It’s a common problem with this engine, which goes in other Nissan vehicles too. But Nissan would not cover the timing chain work, which cost $1,750, claiming that adjustments are normal. But they didn’t have to adjust the tensioners, they had to replace them – just a few thousand miles over the drive train warranty. The adjusters apparently are made of plastic that just wears out quickly. Why does it require class action lawsuits to get automakers to stand behind their products?

FYI, according to web posts, Nissan has covered the timing chain work for some customers, but they won’t explain why some owners get coverage and others do not. They’ve lost me as a customer forever.

Regarding the transmission problem, almost every car made has a trans fluid cooler inside the radiator and it’s been that way for eons. Sometimes problems develop and it may be related to failure to change the engine coolant as specified in the owners manual.
So was the engine coolant changed at 30k miles?

As to the timing chain, many cars use plastic tensioners and that’s also been done for eons. Failure of the chain and tensioners in most cases is due to oil changes not being regular enough and/or running the engine low on oil.
That leads into the rhetorical question of how often (time and mileage wise) you have the engine oil and filter changed.

As to why Nissan covers the chain for some and not others, it could be that they’re basing it on customer vehicle purchase history and maintenance history.

All maintenance was done on schedule. Both of these problems are common for this engine. The radiator problem is an admitted defect. I do suspect you are right about purchase history. I bought a Nissan back in 1994, but none between that one and the Xterra. I was asked about my purchase history when I filed the complaint, and the Nissan rep talked to the dealer before denying the request. It appears you have to be an A-list customer to get any respect.