I've had my 2009 Xterra S for around 8 months now. When I first got it, it was great with strong, torquey acceleration. But over the past couple of months, it feels like it's gotten "soft". In addition, the engine RPMs seem to "wander" and the engine often feels/sounds like it's "bogging". Is this indicative of a possible torque converter slippage problem? The truck is also slow to down shift and can also be slow to shift into reverse.

Also, in most other automatics I've owned, the car will move if it's in gear and you take your foot off the brake. Not my Xterra, though. If you're in gear and you take your foot off the brake, it will just sit there (unless I'm on a hill) until I press the gas. This also leads me to believe that there may be an issue with the torque converter.

One other thing I've noticed is that when driving on the highway with the cruise control on, if I go down a hill, the truck will sometimes slow down considerably as if trying to compensate for the hill, but it will over-compensate and slow down like 5 or 10 miles per hour. There have been times when I thought that the cruise control had switched off because the truck slowed down so much. I'm wondering if this might be a related problem.

When I first got the truck, I used to hear a metallic vibrating sound from under the truck on and off. I thought it was just a scuff plate or heat shield that was coming into contact with another part under the truck and making the vibrating noise. I don't hear that sound anymore, which leads me to believe that maybe something in the torque convertor may have previously been a little loose and causing that sound, and now it's gotten looser, so the vibrating sound has gone away, even though the root problem may be worse.

Can anyone tell me if the above sounds like a torque converter issue? I'd like to be able to tell the dealer as much detail as possible about this issue. Otherwise, I know they'll likely just give it back to me an say "we couldm't find anything wrong with it", and I'll be left frustrated with an underperforming Xterra! I love the truck, but I want it back the way it was!

Thanks in advance for any insight that others may have on this, or if anyone has had similar experience with their Xterra.