Rough 2nd to 3rd gear shift on 2005 5AT
 

Hey guys, I just got my G35 a few weeks ago and am loving every minute of it! I have the RWD G35 with 5AT. I only have about 750 miles on it so far, but I have noticed that when the transmission shifts from 2nd to 3rd gear it feels a little rough sometimes, almost like a light driveline shudder. This usually seems to happen when I'm under pretty light acceleration and the shift occurs somewhere around 3000 rpm. If I mosh it a little harder and get it to shift around 4000 to 4500rpm it doesn't seem to do it. I haven't tested how it shifts at higher rpm as I am still breaking it in. I had to take the car up to 6k rpm one time to merge into traffic but that was in 1st gear and it hit second gear around 6000. When I hit 1000-1200 miles I'll open it up a little more and see what kind of shift quality I get (2nd/3rd) at the higher rpm ranges. Just curious if anyone else has experienced anything like this? Could it be due in part to the transmission learning my driving habits?

Just hit 1050 miles and have had no issue like what you describe.

If it continues, I'd have it checked out. That doesn't sound like anything typical or "normal".

Unfortunately, the 2nd to 3rd is always the roughest on the 5at. We had numerous threads on this rough shift. Some of us hear a "thump" sound with no shuddering...some feel and hear both. I took it to the dealership to inspect and they said this is normal. I've done this search on the 350Z forums and some have it there too but none have had any problems with the 5at. Basically, the tranny doesn't want to shift at certain rpms dependent upon the position of the throttle. You are basically short-shifting when the tranny wants to rev out a little more. Hope this helps.

I suggest you read this thread regarding grounding kit that might help your situation. I have a 03.5 sedan 5AT and experienced the same type of delay from 2nd to 3rd gear. After the grounding kit was installed, the problem went away for good.
I bought the 7 wire earthing kit from ebay, cost me only $12 bucks if I recall correctly. There are many reviews (good and bad) in this thread (https://g35driver.com/forums/faq-diy/3235-hyper-ground-earthing-kit-resource-thread.html), I'm one of them and gave a good review for the grounding kit in general.

I've noticed this my 05 5AT. I notice it more often in MM when short shifting into 3rd..it's a little more sudden/firm than the other shifts and sometimes i can feel a little shudder. I agree with the previous post about it happening when you force the transmission to shift earlier than it would've shifted in auto mode under same amount of throttle. I've never felt it in full auto mode. I'm not too concerned about it. If it gets worse or impacts other areas of the drivetrain - we're covered for 60,000mi anyway.

BTW, the traction difference between a full tank and near empty is remarkable. In manual mode it's easy to spin even with LSD when low on gas...but when full it takes a more deliberate effort to break the tires loose.