Postby smj999smj » Fri Sep 28, 2012 5:20 pm
If the vehicle is under warranty, I would definitely have it checked by a dealer. If not, a service wouldn't be a bad idea, but if these "pieces" are substantial in size, it could be the sign of an internal hard part breaking down, especially if what you describe as "pieces" is a roller from a thrust bearing. Metal shavings do sometimes occur from normal wear and tear and will usually fall to the bottom of the pan where they will stick to the magnet.
As far as the service, you can take it to an independant shop, if you wish, as opposed to a dealer. Make sure they service it with an ATF that is recommended for use in Nissan Type "J" or "S" applications. It's really not that difficult to do yourself and you could save yourself a lot of money; it's actually easier than doing an oil and filter change. All you need is a drain pan that can hold a gallon of waste oil, a 19MM (or 3/4") box wrench (longer the better, for more leverage). You'll also need a transmission funnel. You'll need a new drain plug washer; you can get one from Nissan (Nissan P/N: 11128-01M0B) or from your local auto parts store (Size: M12-1.25). You'll also need 4 quarts of ATF. If you want the genuine Nissan ATF, you can go to your local dealer and pick up 4 quarts of Nissan Type "S" ATF for around $9/quart. Personally, I go to Advance Auto Parts and get a 1-gallon jug of Valvoline Maxlife ATF for around $18. ANother ATF that will work and can usually be found in your local Walmart or auto parts store is Castrol Multi-Import ATF, which runs about $6.50/quart.
Take a short drive to get the fluid warm and park it. The Pathfinder is high enough that you may not even need to jack it up, depending on your size. If you do, make sure you support it with jackstands for safety's sake. Take out the 19MM drain plug and drain the old ATF into the pan. I use a razor blade to help get the old drain plug gasket off. Install the new gasket onto the drain plug and reinstall when the ATF is done draining. Dispose of the old ATF responsibly (many auto repair shops or even Walmarts with auto centers will take your old oil). Remove the dipstick and insert the trans funnel. Most need just a little under 4 quarts, so pour in approx. 3-3/4 quarts. Start the vehicle, let it run for a few minutes, remove the funnel and check the level with the dipstick. Top off the ATF as needed and make sure there is no leak from the drain plug. That's it!