I recently purchased a 2007 H3 with ~28,000 miles on the clock. I love it, but it looks like the previous owner may have never rotated the tires; the back 2 are more worn (i.e. less tread) than the front 2. Is this consistent with what you all have seen? I would have expected the front tires to be more worn, and I wonder if the dealer rotated them before selling the vehicle ... I should have asked when I bought it .

Also, via the search, I've noticed a couple other folks with a similar problem but no resolution regarding a "chugging" feeling after the torque converter clutch locks up. Basically, once it's going about 45MPH (or more) in top gear, and it's under light load, the torque converter clutch engages after which the vehicle has a mild "chugging". The sensation dissipates as you get up to expressway speeds, but it's definitely noticeable between 45 and 55MPH. It doesn't happen if you play with the gas enough to prevent the tcc from engaging, so I don't believe it's a tire or alignment issue, but I'm hoping you guys can shed some light on potential problems before I take it in.

Thanks in advance.

 

My experience with my H3 (2007) is that the front tires wear faster than the rear, so I suspect the dealer or previous owner rotated yours before selling it...

Can't help for the 'chugging' issue.

 

Buy a new set of tires first to establish the baseline and don't forget to rotate them often.

With old, worn, and likely scalloped, non-rotated tires, diagnosing your Chugging issue will be very difficult.

 

Don't know what you mean by chugging exactly, but at 45mph +/- the TQ converter locks up for overdrive (not a true overdrive, but pretty close). The gearing in the 3 is not perfect in that speed range you described between 45 and 55 or so. What I mean is you have a near 6000# vehicle with its RPMs below its midrange power band and it doesn't respond well to being pushed up to more speed/RPMs slowly, so often the TQ converter unlocks to put the RPMs higher quickly.

You will get mush better MPG if you stay in the locked up mode, and just be patient if you have to speed up a little. I do not think your chugging is related to tires, but just how the weight, gearing, engine RPM, and TQ converter all work together. The engine is just loafing and temporarily not in the best gear range.

 

I should be more descriptive in the "chugging" sensation. Basically, once the torque converter clutch is locked (and stays locked during cruising or gradual acceleration/deceleration) there is a mild, back and forth vibration as if there is tension in the driveline that builds and releases rapidly. It's hard to describe, but it is more of a vibration than a surging sensation.

Ultimately, I'll take it into a dealer to get their opinion, but I wanted to see what you guys thought or if you had similar experience.

Thanks for the responses, and let me know if you have any other ideas.

 

That "chugging" used to happen to my old H3 all the time at 45 mph. It was the 5 cylinder version. It just seemed to hate going 45.

 

my h3t does that same chugging at about 55mph to 60mph. I spoke to Kelly at PCM for less and she says it's a pretty common problem in the I5 engine combo. It's more annoying than anything, but a tune will take care of it.

 

My 2007 did this exact same thing! I bought it used and the previous owner NEVER rotated the tires. After buying new tires the "chugging" went away. Mine was so bad it literally made you sick to drive for more than an hour. 46mph was the worst, but it's all better now!

 

Also I forgot to add, I took it to 2 GM dealers before I found out it just needed tires. The first dealer where I bought it used from was juts a Chevy dealer, they supposedly balanced the tires (not for free) and told me "that's just the way hummers are". The second dealer was an actual hummer dealer, they told me there was NO WAY the first dealer balanced the tires! They said the tires were so bad they couldn't be balanced. But the tires that looked the best were actually the worst, they gave me an awesome deal on 4 new tires!