6th to 5th downshifting crunch noise!?

[GeorgeGegham]

I've been noticing lately, downshifting QUICKLY into 5th gear from 6th will create a scratching type of noise, but if I do it very slowly it will work fine. Very cringy. From Google i'm assuming this is an extremely common problem amongst Z's, currently a 2010 370Z and I just hit 19k miles experiencing this, (Got it at 17k). I'm not under a warranty either.
Any one know what the right thing to do here would be? Cheapest way as well.

[kenchan]

Step on clutch fully, let syncros do its job. Free

[SouthArk370Z]

Originally Posted by GeorgeGegham

... downshifting QUICKLY into 5th gear from 6th will create a scratching type of noise, but if I do it very slowly it will work fine. ...

Sounds like either the clutch is not disengaging properly or the synchro is getting worn. It might help to change the trans lube and maybe switch to a high performance lube. Plenty of threads about which lube is "best." Clutch system test/adjustment procedures should be in the FSM.

[barncobob]

change lube, cheap fix if it works,,dont cheap out on fluid

[Haboob]

I had a similar issue in my previous car and it was that the clutch lever was worn out (it got so bad that it'd pop out of gear and/or want to stall when taking off from a dead stop).

Could be synchro's too.

[srbrubak]

I had the opposite problem. When shifting from 5th to 6th under any kind of load I would get a nasty grinding. If I shifted slowly and carefully, all was fine. I took it to the dealer, told them about the problem, they verified the problem, and since I was still under warranty, Nissan replaced my transmission for free. Now everything shifts fine. I forgot to ask the dealer if Nissan gave me a new or factory rebuilt tranny. I had 27,000 miles on my Z and had this done in October, 2015 since my warranty expired in November, 2015.

[kenchan]

yah, i read of one other case in the last 7yrs where a guy's 6th grinded no matter wat. dealer gave him a new syncro.

[edub370]

Originally Posted by kenchan

yah, i read of one other case in the last 7yrs where a guy's 6th grinded no matter wat. dealer gave him a new syncro.

i was that guy. 6th gear synchro went. trans replaced under warranty. digitonium had this issue with a couple transmissions as well think

[JARblue]

As everyone else has mentioned ... synchros are going. If under warranty, Nissan will replace the whole transmission to fix them. Otherwise, don't worry about it. Just be patient with the shift so that it doesn't grind.

[kenchan]

Originally Posted by edub370

i was that guy. 6th gear synchro went. trans replaced under warranty. digitonium had this issue with a couple transmissions as well think

was it? dang... i thought the guy (u?) had just the syncro replaced. regardless

then was that u that said the dealer did a f-ked up installation and u had to go back to realign the gates?

[edub370]

Originally Posted by kenchan

was it? dang... i thought the guy (u?) had just the syncro replaced. regardless

then was that u that said the dealer did a f-ked up installation and u had to go back to realign the gates?

hah that was not me. maybe there are more 6th gear synchro failures than anyone knew?

[JARblue]

Originally Posted by kenchan

i thought the guy had just the syncro replaced.

FWIW, I went back and forth with my warranty company on this. They insisted that my 5th-6th gear synchros could be serviced by a transmission shop. But two different Nissan dealers confirmed that they do not work on internal parts on the 370Z MT and that they would replace the entire transmission.

I will likely end up having the dealer do the work because the warranty company is making it too much of a hassle to bother saving them money. I was hoping to buy the transmission myself from Z1 and then pay a competent shop for labor and have them install a new clutch and flywheel at the same time.

[mishuko]

I think best bet would bet to swap all the synchr's at the same time. atleast if there was any abnormal wear on the others it won't be an issue

[kenchan]

Originally Posted by edub370

hah that was not me. maybe there are more 6th gear synchro failures than anyone knew?

yah, cause i thought the guy had a 09 and the issue popped up around fall or winter of 2009..

[GeorgeGegham]

Originally Posted by JARblue

As everyone else has mentioned ... synchros are going. If under warranty, Nissan will replace the whole transmission to fix them. Otherwise, don't worry about it. Just be patient with the shift so that it doesn't grind.

Yeah i'm not really in the budget for an entire new transmission at the moment.. How much do those go for anyway? And will it everything be good if I leave it be for now; slow shifts from 5th, etc.?