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.

Hmmm, That is interesting and I see where you're going with this but look at it differently for just a minute. I think Torque converter could = symptom not "problem"

Do all the routine stuff like check the AT fluid per the manual (truck and tranny must be warmed up, parked on level ground, engine running and in park..etc.) if it’s not immediately oblivious take it back in and have it looked at..it’s still under warranty right?

-Good Luck,
Saturday

Thanks for your response, Saturday.

Good suggestion checking the tranny fluid. I'll do that next chance I get.

The reason I went to the torque converter is due to a past experience I had. My mother and I both used to have '94 Mustang GTs. One time I drove hers and noticed that it didn't have near the "snap" in terms of accelleration and it just felt sluggish compared to mine. I mentioned it to her and she mentioned it to the dealer. Upon hearing her complaint, one of the mechanics in the shop said that he new what the issue was and it had to do with the torque converter. He made some adjustments to the TC and it was like a whole new car. The performance I'm seeing from my Xterra lately "feels" like what I experienced with my mother's Mustang.

I can definitely take it to the dealer, but I know how these types of complaints normally go in a dealership shop. Not wanting to spend a alot of time chasing a vague issue, they will simply say that they don't see any problem and that it's "normal", unless I can give them as specific information as I can to track down the issue.

Then again, maybe it's all in my head and this is just how Xterra's are. It sure seemed like it ran much stronger, before, though. It's only got 8,500 miles on it.

So, I'll pose these questions to recent model year Xterra owners with auto transmissions:

- When you take your foot off the brake when the truck is in drive, does it roll, or do you have to give it gas for it to move? Most automatic cars/trucks I've driven will role when you lift your foot off the gas. My Xterra does not. Does this indicate a potential issue?

- When you get to a hill on a normal road, does the truck slow down significantly and you have to force a downshift by almost flooring the gas to maintain speed?

- Does the truck never seem to be in the "right" gear? It seems like the truck is always either "bogging" out or I have to nail the gas to get it to downshift, in which case it takes off like a bat-out-of-hell! Is there no way to just get moderate, smooth acceleration from this truck?

Is the above normal for the Xterra, or is my truck not performing properly?

Fair enough. I completely agree with your description of how a dealer would likely 'handle' the problem. I did think about adding a couple other ideas mostly having to do with the engine not the tranny but didn't take the time to include them since you're still within the warranty period. Oh well - here goes - My other ideas had to do with a. engine performance and b. vacuum leak/computer issue. Believe it or not little tune up issues like a malfunctioning sensor, slightly off ignition timing or poor fuel delivery could result in nearly identical symptoms to those described above. Not saying that those are the problem - it's just that a whole host of things can produce similar symptoms so keep an open mind.

The other thought (part b.) was that in older models (before electronically controlled transmissions were the norm) the transmission had a vacuum line from the engine. Now days I believe they are nearly all electronically (computer) controlled. It used to be that something as simple as a vacuum leak would often mess with the shift points making the transmission shift weird and also bog down the engine idle a bit so that it would not roll forward on its own or roll backwards on a hill etc. these days it’s more likely to be a software issue where something needs a software update.

So when you take it in – don’t forget to mention that you think the engine is down on power as well – they may find that needs something like a simple software upgrade but it could just as easily be a faulty sensor on the engine.

I can’t accurately answer your other questions about does the truck roll forward on its own (yes, mine does) or backwards on a hill (no, mine doesn’t) because mine is an older (2000) and idles around 750 rpm – which is plenty enough power to hold the truck steady – it is possible that newer models may have a slower idle speed but I’ll let someone with an newer model respond.

-Saturday

Thanks very much for your suggestions. A software update did come to my mind as a potential resolution, also.

I would think that a faulty sensor would throw a code and the check engine light would come on, but maybe not?

I will be sure to mention the engine power issue to them. I also find that it seems to vibrate when idling in gear, which I'm not sure is normal, either. I understand that the Xterra isn't a Mercedes Benz, so it might not be refined to the point of no engine/drivetrain vibration, but in this day and age, I wouldn't expect a new car or truck to vibrate when idling, either. i was wondering if that might be another symptom of the issue. I could be off on this one, though. Maybe vibration at idle is normal for the Xterra. I'll add that to the questions:

Does anyone else with a recent model year Xterra experience engine/drivetrain vibration when idling?

Doesn't sound like a torque converter issue, more like a learned response to your driving.

Are you the only driver? The main driver?

Disconnect the battery for an hour or so and see if it still does it. If it 'fixes' it, then the Transmission Control Module (TCM) has learned something that made it act that way. If it's acting the same when you reconnect the battery, then there's probably an issue and you should take it back to the dealer with your complaint.

Don't try to tell them something that you think they'll act on, tell them exactly what it's doing/not doing. The TSB's that the techs have access to nowadays are pretty specific. I don't see anything for the '09, but they can always call Tech Hotline with the complaint and get the latest and greatest.

I'm betting you're going to end up at the dealer anyway.