My 08 350z with 21k miles will grind the gears and I cannot put it into gear for several seconds if I launch and then try to shift into second at close to redline. Also, if I kinda get on it and then decide to go into sixth and begin driving normally, it will grind into sixth occasionally. I would just like help diagnosing what is causing the problem and I apologize in advance if there is a related post. Thanks guys

 

Have you check your shifter alignment?

 

I assume that the Z is under warranty? Well go get it fixed.

 

Is this your first manual transmission? I think the problem may be more driver error than transmission problem. How does it shift when you are not "on it and driving hard"? I'm not sure I understand how you are putting the car into 6th gear. Are you saying you accelerate hard in 1st and 2nd and then go directly to 6th gear? I'm just trying to get a better understanding.

 

Yes I'm saying like if for example I was going to merge onto the highway and I went wot through first and second and then once up to about 60 went into sixth it will grind. I know how to shift, definitely a mechanical problem not driver error haha. It is worse after clutch gets hot from driving it hard. And I don't just get it fixed under warranty because if my clutch is the problem its not covered.

 

Driver error, sorry guy, but I can see it from here. You can't just slam the gear lever around without matching the revs between the engine and gearbox. Drive next to some 18-wheeler's and listen/learn to how those guys do it. Yes, your gearbox has synchro's. which 18-wheeler's don't, but you've at least got to get your revs in the ballpark.

 

Driver error my friend. I know, because I've done it as well. If you get in too much of a hurry with the Z transmissions it won't cooperate. The more and more you practice, however, the better it should get. I wouldn't recommend jumping gears around like that. Just punch through the gears smoothly until you rest in the gear you want. If you're still having an issue, look into some redline MT-85 transmission fluid. I know Z1 carries it, and it's helped smooth out my '03 a lot, and my transmission has a history of having more problems than yours. Hopefully your synchros aren't already bad though

Best of luck though.

 

Sounds like SOME driver error as mentioned before, I suggest going to the dealership and replicatijg it for them if you're still under warranty (HURRY). I Had my trans/clutch/flywheel replaced on my 08 with 23 k miles on it. On Nissan's dime BTW. Don't say its when you're "drag racing" or anything and they SHOULD take care if it. Like posted before, go through all the gears instead of jumping. Hope this helps!