Postby smj999smj » Sat Feb 22, 2020 4:08 am
The 05-06 models tend to be the most problematic when it comes to the initial "bugs." The transmission is actually very good on these trucks; the majority of the failures is not because of the transmission, itself, but because of the trans cooler in the radiator leaking and dumping coolant into the transmission fluid. If you did the bypass, you won't have to worry about that. The problem is not known on aftermarket radiators, so, if you want to maintain the advantage of having the radiator's trans cooler---which also warms the fluid and keeps it at optimal temperature---you can simply replace it. Rockauto.com has units for $100 that work just fine!
Some of the other problems that occur on these transmissions include the metal pin tracks breaking between the TCM and valve body (which can be repaired by soldering, PNP switch failures (which are part of the TCM/valve body) and speed sensor failure (one's on top of the valve body and one is in the extension housing), but none of these I would consider a "common" failure.
The biggest issue with the engines is sometimes the upper timing chains can cut into or through the plastic chain tensioner faces. This was caused by worn tooling improperly stamping the upper timing chain links. The indication of the problem is a "whining" noise that increases with engine speed from the front of the engine. This occurs to "some" 2005-2010 V6 Pathfinders/Xterras/Frontiers, but not all. For those that do get the problem, replacing the upper timing chains and tensioner faces fixes the problem for good.
As far as electrical issues, I don't think they are any more prone than any other modern vehicle. I have an 06 and an 08 Pathfinder which have, combined, 450,000 miles on them. I replaced the timing chains and radiators on both of them and the fuel sender on the 08, but they've been pretty reliable, otherwise. Most of the other repairs have been wear items like brakes, struts, etc.