Hey guys,
I just recently purchased a 2012 Yukon SLT with 57k miles. The car seems to be in great shape overall, but I'm definitely new to the world of Yukons/Tahoes...so I'm hoping you all could offer some expert guidance.
I did do some searching in these forums beforehand about my problem and I'll share what I found below.
Main problem: when I drive on city streets and get to around 30 miles or so and start coasting and the RPMs drop to around 1000 or so...I notice this shudder/vibration as soon as I give it a little gas. It completely goes away at about 1100/1200 rpm.
I kept trying to pinpoint if it was more connected to speed or RPMs and I realized that it was mostly about the RPMs. Even if I'm going 40 or whatever...once it drops down to 1000RPM and I give it a bit of gas, there goes the vibration.
It's not a really strong shudder/vibration, but it's noticeable and annoying. It drives so smooth beyond that quirk and I'd like to get it addressed.
From the posts I've seen, a few have called out:
- Driveshaft alignment
- Torque converter
- U-joint
I'm curious what you all think.
Beyond that main issue, I noticed a few more small quirks:
1) a very slight whining when I turn. Is it normal to whine a bit or could that be a power steering issue surfacing?
2) vehicle start is a little slow in the beginning, almost like the battery is going. It turns over a little slow and then starts right up. I am guessing if I get the battery checked, they'll be able to check the alternator too? Been a while since I've had an issue like this.
3) the vehicle has remote start and it doesn't seem to work if the car has been sitting a bit. but if I click the lock button then hit remote start, it works. I wonder if that's somehow connected to the battery/start issue.
Thanks in advance for any help you can offer!
I have a 2007 Yukon (kind of the worst case for AFM issues) and I have never had the shudder you describe. I have read others who have had it, so I know it is real and the way you describe when it happens, it sure sounds like your AFM switching from V4 to V8 mode is the trigger.
I turned AFM off on my Yukon with a Diablo Predator 2 tuning device. All the AFM hardware is still there, it just doesn't switch back and forth. I think in later model years like yours, a lot of the AFM issues have been addressed (the ones that may actually lead to a more substantial engine problem), but I don't think they are 100% problem free.
I would also heed what
@Geotrash noted about the actual source of the shudder. Maybe have a competent transmission tech take a test drive and see what they think.
Along with Foggy's list of good things to do, maybe consider one of the many ways to turn AFM off in your engine. It might be as little as $50 for an ECM reflash to turn it off, I think most on these threads would consider it money well spent.
Finally, on the slight whining when turning. If your Yukon is 4WD and you have the option of 2WD, Auto, 4WD high and 4WD low, make sure you have it in 2WD and see if it is still whining. If you were in 2WD and get the whining, it is more likely steering than transfer case noise.
