I have an 08 G37. Soon after I bought the car I noticed a whine that would change in pitch in between gears, and my engagement point was way too high. That transmission was replaced under warranty. The new transmission developed the same whine, but even nastier. It's almost a howl at this point. On top of that, there is tapping/clicking noise upon engagement. The whine/howl goes away if the clutch is pressed in. But the tapping can be heard intermittently when the clutch is pressed in. None of my local Infiniti dealerships want to deal with it. The transmission is also very notchy, and slightly lurches forward when going into first. I'm pretty sure it's the throw out bearing that's making all the noise. I'm probably just going to get the heavy duty zspeed throwout bearing, along with the South Bend clutch kit/flywheel.

Mine had a nasty whine from about 1K miles (bought new). It was very annoying, especially at lower speeds in the lower gears with the radio off. Sounded similar to a super charger whine. Test drove a few others at the dealer and was concluded it is standard noise for these cars. While in motion, with the clutch pedal to the floor, varying engine rpm would vary the pitch. Still trans related as doing the same thing while standing still resulted in no whine. The sound was most prominent between 2-3K rpm (regardless of gear), and was still present at higher revs but was drowned out by engine noise.

This drove me nuts. A $40K infiniti should not be making such sounds, even if it is a 6mt. On advice of those here and on the G site, at ~7500 miles, I changed out the trans fluid to redline MT85 (3.xx qts). First test drive yielded no improvement. Subsequently though, the sound was greatly diminished. It's still there, but nowhere as annoying as it was. While I wish it was gone completely, I can tolerate it now.

For $60 in fluid (you need to get 4qts as it takes slightly more than 3), it was a cheap experiment. It's now about 3500 miles later and the noise hasn't gotten louder. It's about the same as it was after a few hundred miles following the fluid change. The initial test drive after fluid change was only ~5-10 miles, so my guess is it needed a few heat cycles and more miles to fully coat all of the trans internals.

The tapping/clicking noise sounds like your shifter isn't going through the gates smoothly. There is an adjustment/alignment procedure when reinstalling the trans/shifter. You say the whine/howl goes away with the clutch pressed in. While this is happening, what's going on with the engine revs? Is it falling back to idle, or is at the same engine rpm for the speed/gear you were in?

The slight lurch forward when engaging firsts suggests the clutch isn't fully disengaged. I remember test driving a G or Z that had after market clutch and other performance mods. Getting it into first was quite the challenge.

The tapping isn't affected by the shifter or its position. It only happens when the clutch is fully pressed in or upon engagement, can be heard gears in gears 1-3, happens in other gears but harder to spot because of the road noise at higher speeds. The whine goes away if you press the clutch and rev it up or let it idle, I've played with whine and when it comes/goes in every way imaginable. My local indy Nissan shop thinks it's the throw out bearing.

My latest transmission has 3rd gear whine, but it's not too bad. I've had redline fluid put in on the same day of the installation, and I've not felt the notchiness. Overall, the gearbox is very tight and feels very good. Too bad they can't build them as consistent.

Has anyone here every pulled their own transmission apart and rebuilt it? If/When mine ever goes I will pull it apart and repair it myself.

As long as your gears aren't destroyed, ditch those brass synchros for something better. You can probably do some other gearbox upgrades for tighter shifting (remove worn parts).

Been trying to track down anything as far as transmission mods go, seems like no one has spent any time beefing these up.

LafitteZ is the only member I've seen so far with a custom upgrade:
http://www.the370z.com/engine-drivet...nsmission.html

Yup, I been waiting to hear if he got ahold of whoever built his trans. Thanks for the reminder.

i cringe as i read peoples posts in here. after going thru three manual trannys in my old IS300 im very worried about any odd sounds or funky feelings in the transmission.

Mine has taken all kinds of abuse so far. Im amazed that you guys have issues especially if you baby them. Mine gets all 430 ftlbs everyday I drive it, and has not broke a sweat yet.

My new trans feels pretty darn good, granted I only put 10 miles on it haha.

Did you fill it up with Redline fluid yet? I had mine done the same day of install.

I did not, I need to get some. The one that failed had redline in tho haha... With the short shifter it feels darn good, im sure the redline will smooth it out a bit more.

i cant believe you are got a 3rd transmission with TT's. If it was my old mustang with my SC and my tranny went, no WAY ford would give me a new tranny!