5th and 6th Gears Grind
 

I somewhat recently bought my 350z at the end of February, and since I've owned it 5th and 6th gear grind when I shift in to them. I can get around this by double clutching, but occasionally even then it still grinds. I've been told this was a problem due to the sync rows? I guess I would just like to know the possible problem, and the cost.

Also, I replaced my clutch with an aftermarket one, and the shop had to replace my flywheel (another aftermarket piece as well), due to messing it up themselves. Since then, I've noticed a weird scraping noise occasionally. It seems to occur more at slower speeds. I'm assuming it's the flywheel, but what did they do to it to make it sound like that? Did they just install it wrong?

I currently don't have to drive my car due to a temporary move, but I'm planning on fixing these issues when I get back. Mind you, I'm young and don't have the luxury of dropping cash to get these issues fixed on the spot, I have to save. I've been told around 1500, and I just want to know if this is an accurate estimate so I'm prepared.

this has been a problem even back with the Z32's (300zx) I had it in mine........... however my 370 has yet to grind!
common fix is to upgrade the transmission fluid, I used Redline MT-90 oil on my Z32 pretty much fixed any to all grinding IMO! o ya but MT-90 is for manual transmission cars only.....I dunno what autos are I have never really worked on any.


As far as the fly wheel issue it could be making the noise, however if they did break a part on your car while doing work on it causing them to replace it. Then there is a 99% chance that I am not going to go back to them........

this is super common with the Zs and their trannies .... need a rebuild or new one unfortuneatly syncros are shot

Oh, so you even had the faster one :p Yeah, I took it to a custom shop for them to install my clutch, and they said when they took the flywheel to be sanded down (by another garage), they sanded it down too much. If that's not the right term, bare with me, I'm not a car guru lol. So I don't think I'll be taking it back to them. I did have them change the transmission fluid (though I don't know with what kind), and the grind is still there.

Ok, the syncros is what I was expecting it to be. I'm planning on taking it to the dealer to be fixed, I don't think I want anyone else messing with the transmission.

I hope this oil switch works.
I was unaware of this Z problem. When I rebuilt my 280 transmission at 175,000 miles, the synchro gears were reused. No problems with my 300. Does revving the engine to match clutch engagement (like the sync rev button) extend life of synchro gears?