Hi,
I'm about to bring mine in for its first oil change and I have a couple of issues I want to address. But I wanted to get feedback from other owners first to see if these things are normal or if anyone else has more info on them.

1. I hear a loud creak/popping noise from the rear part of the roof when the body is being twisted, such as when turning into a driveway at an angle.

2. The transmission (auto) shifts hard under full throttle. I've seen this one mentioned in a couple of other posts, so maybe it's normal? Has anyone talked to the dealer about it?

3. This one is a little more obscure and infrequent. It occurs when driving on the fwy in slow traffic (not stop and go) where my speed is varying from, say, 10 to 40 mph. You know the routine: cruise a bit, coast, accelerate lightly, slow down, accelerate again, etc. Once in a while, just as I'm tipping back into the throttle - BAM! -- there's a huge clunk just as the power comes on. I feel it and hear it and it's violent enough to make me worry about damage to the tranny. It almost seems like it's just in the process of picking a lower gear and the power comes back on at exactly the wrong moment. It's only happened about 3 times total, so it won't be easy for them to duplicate. I'm hoping it might be a known issue.

Any feedback would be appreciated!

Thanks all,
Richard

 

take it to the dealer and tell them your problems.

 

I had #1 as the problem. The problem was ice buildup on the base of the rear window (or anywhere on the rear window). Keeping the rear defroster on when there was ice buildup took care of the problem.

 

#3 is because u have an auto.
the tranny is about the shift into say a higher gear for coasting and u give it a lil gass, so the tranny stops mid shift and changes its destination gear. all automatics do it. It is VERY hard to duplicate. but it is normal.

 

I hear ya Snowcross. I know that sometimes a set of conditions can cause an automatic to get "caught out" and shift hard now and then. But I'm an old geezer of 47 and in 30+ years of driving I've never felt anything like this. Something's definitely amiss, I'm just curious if anyone else has experienced it.

I'll update the thread after I take it to the dealer. If they're not familiar with the problem, I may just put a tape recorder on the passenger seat when I'm in that kind of traffic. That way, they could at least hear the bang.

 

mm thats not good then,
when you go to the dealer be sure to tell them that it is not what i explained above, because they would probably think that as i did

 

Good point, I'll be sure to clarify that. Thanks!

 

I get this occasionally. Not that big of a deal to me.

My car and all of the 07 and 08 G35 ATs I've driven does this. It's normal and I actually like it. It's good that the shifts are firmer and quicker when you are driving fast. It would feel really lame if you were accelerating hard and the car was lolly-gagging gradually from gear to gear. It would feel like that crappy feeling I got when I test drove a Lexus GS350.

I have not experienced this. What I have noticed is the throttle is not linear at all. Sometimes a little gas will give you a massive 2 gear downshift and massive acceleration. Other times, you can tip into the throttle and the car just acts a bit sluggish. I have felt that thrown back hard into the seat feeling when I just tip in the throttle, but my transmission has never made loud banging noises or slammed into a lower gear violently in these situations.

 

Automatic transmissions are generally (especially on sports cars) designed to shift hard when under full throttle lol. If you're going full throttle, you want it to shift fast...the last thing you want your transmission doing at 7,000rpm is a slow engagement of the next gear. That'll burn up your bands in a hurry and toast your transmission.

IF ANYTHING...you would want your transmission to shift quick and hard in all applications. But comfort becomes an issue.

Think of it this way...when you're driving a manual and you slowly engage a gear...you're just rubbing two metals (so to speak) together until they gain enough friction to grab 100%. Long, slow engagements will just wear that friction material off faster and you'll be replacing your clutch sooner than imagined. Automatic transmissions (in general) use line pressure to determine how fast/hard the engagement is going to be. Higher the line pressure, the harder you're working your car, the later the shift will be and the harder it will engage.

Of course, that's theoretically and speaking in general. Modern transmission are a lot more complicated with solenoid actuated bands, etc.

I hope this makes sense.