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Old 12-18-2011, 11:00 AM   #1 (permalink)
Mike S.
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Join Date: Aug 2010
Location: Buffalo
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Drives: 09 G37xS
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Default More thoughts on the 7AT from a future buyer...

I test drove a new 2011 370z Touring (no sport) 7AT last weekend. I liked it. In this thread, I'm really just posting about the 7AT drivability. It felt really very similar so my G37x, except just much quicker. The Z is about 500lbs lighter.

However, the gears are the same and so is the final drive. Now the reason for my worry is that the G37 boards are riddled with 7AT complaints. Its not that its a bad tranny, just the software, at least in the G, is messed up in many ways. Infiniti has released TWO software updates since 2009 to correct it and it still hasn't fully.

I did notice than when the Z was cold and I was coming to a stop (just in standard "D" mode) that it held on to 2nd gear until like 2mph then kind of jerked into 1st. My G does the same thing when cold (actually worse).

My hope is that Nissan has tuned the 7AT more aggressively in the Z (firmer shifts?) and that the problems seen in the G line aren't in the Z. I would imagine that if they were, I'd see posts here.

Here are some of the problems the Infiniti G 7AT have had:

1. When first released in 2009, the downshifting slowly for stop under 30mph was aggressive enough that you could basically roll to a stop without using the brakes! It wasn't harsh downshifting, just kind of kept the tach at around 1500 as it kept choosing lower gears. Coasting in city driving was not possible LOL. A re-flash of the TCU corrected this.

2. Harsh 3-2 or 2-1 downshift. This would/will occur when braking for stop (not downshifting for acceleration). Sometimes it feels like a little jolt.

3. "Flare". The 7AT has a Variable-Locking Torque Converter. Not sure why, or how it helps, but it makes the tranny very busy. After my car is at operating temp and is then restarted (say I run into a store for 20 mins), when I come out and drive away, the rpms will jump as its shifting from 3-4 or 4-5. Almost like its slipping. It's basically the torque converter unlocking (producing a split second rise in rpm's) and then re-locking a split second later.

So I post all this because I've come to hate the 7AT in my car, even though it does drive well when you're more aggressive. However, on the Z boards, it seems all is rosy when the tranny.

Here is a link to the Infiniti Technical Bulletin for the latest transmission software update. BTW: They updated the ecu in this update too.

[TSB] G37 7AT shift issues TCM/ECM reprogram - MyG37
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