My 6MT lost its syncros twice while under warranty. My warranty is over now, and I'm starting to see the first symptoms of syncro wear on 3rd gear. Replacing the transmission is way expensive, rebuilding the affected gear (and probably 5th and 6th) is cheaper, but still a couple of grand.

I have no faith in this transmission design, since I've driven manuals all my life and never had such problems, so I'm considering putting in a reliable transmission, but I have no clue what's possible. Have any of you guys on this forum changed out the transmission in your G's for something different?

 

don't hold your hand on the shifter while driving i don't see why anyone would want to put in a totally different transmission into the G, maybe its the way u drive

 

Nah, it's not the way I drive. My first car didn't wear out syncros at all or need a new clutch until 160k miles. I think I may just be unlucky with the Infiniti gods. I've also had my radio fail several times, differential come apart, driver's seat rip off the floor when I was accelerating, etc .

I'll fix this transmission and see how it goes. The amazing thing is that I don't drive the car very much and I only have 38k miles on it and this is the 3rd time the transmission is going. I've needed transmissions more often than I needed tires!

 

I wonder how far you'd get by contacting Nissan. It's quite obvious that you are having more problems than is ordinary and whatever was fixed under warranty obviously wasn't the root cause of the problem. It's at least worth a try, first asking for help, and then if that doesn't work you can argue that your car was not fixed properly under warranty.

 

what signs of syncro wear are you feeling? i've never had a cars syncros crap out on me before, so i don't know what i'd be feeling for, but i've got a lot of movement in third in gear with acceleration and coasting that i don't have in other gears. got a few months left on drivetrain warranty, want to get this sorted ASAP if that's what you're talking about.

 

Syncros synchronize the rotational speed of the input shaft to the teeth on the gear selector arms. When a syncro is completely dead, you get grinding whenever you shift and don't rev match perfectly. Right now, I occasionally get the grinding when I'm not careful to shift very lightly, meaning that the syncro does some amount of synchronizing, but not enough.

It's an easy fix, I could even do it myself, but the big pain in the butt is dropping the transmission out of the car to do it.

I wouldn't worry about the stick movement in your transmission, it's normal. The shifter sticks directly out of the transmission, so it shows all movements of the transmission. In many other cars, the stick isn't directly attached like that and the linkages hide the movement. My Lotus shifter never budges, despite the fact I can see the engine and transmission jumping back and forth in the back under heavy acceleration. This direct connection in the Infiniti is what gives that really direct, snappy shifter feel.

 

Dude you're highly unlucky. These transmissions are very stout. People are pushing 800+ HP through them with no issues at all. Rather than rebuild your lemon transmission make them replace it instead...