5th gear scratch (not a grind)

NismoNY

Hey guys,

I'm trying to see if the issue I'm having is characteristic of the 6-speed transmission or not. Sometimes, not often, when shifting out of 4th into 5th, it'll slightly "scratch". It is not a grind and can't really be heard the way a grind can be, but it can be slightly felt thru the shifter. This will happen at low rpm as well as high. However, with SRM on, I can't say I've noticed it... more so with SRM off. My car has 17k (2014 Nismo) on it and I've owned it since 12k. So I'm not sure if this happens even with brand new transmissions. If so, then it's fine, but if not, then I'm a little worried. The car has Redline gear oil in the transmission by the way.

I appreciate any input.

Thanks!

JARblue

When you say "scratch" are you referring to something that sounds like a grind but for a shorter length of time?

My 5th and 6th gears have been grinding for a while now due to the synchros going bad. But they don't grind like a mis-shift or something. They just very briefly grind as I enter the gate, so the sound is not near as bad as a mis-shift would sound.

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PharmDZ

I get this occasionally, but it's definitely more of a grind going into 5th from 4th or 6th. More when the car is colder, but still not a great feeling. I'm going to change my transmission fluid again and see if it helps at all.

NismoNY

It's tough to describe to be honest. I had a 350z that would grind from time to time and I for sure know this is not a grind. Fingernails on a chalkboard kind of feeling might be best to describe it. It isn't really audible but can be felt for a very short period of time.

Jsolo

Maybe it's a precursor to a grind? 5th/6th don't engage as smoothly as the lower gears on this car. You can try going with different trans fluid. I'd recommend mt85 but I've had bad luck with it after it accumulated some miles. The car would shift very poorly in the winter (cold) until trans got warmed up.

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MAMotorsports

It sounds like this is just a real slight grind, since you feel it in the shifter.


I would switch out the fluid to some Redline MT85 and see if that helps.

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NismoNY

In the first post I mentioned I have Redline in the transmission

phunk

Mine has scratched 5th for years. Unless racing, I pause briefly before making the shift into 5th to avoid the scratch (which is slang for a really light grind, synchros starting to show wear).

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mishuko

i have this issue too. it's hard to shift into second while car is still warming up. once the clutch and components are warmed up i can shift through the gears with ease.

but i find that the 1-3rd gears are more clunky/rough than going 3-4-5-6... lol maybe we need to teach each other the opposite end of shifting so we be smooth

JARblue

This is exactly my experience. I noticed it as early as 20K miles. It's getting worse over the years despite my efforts to avoid the grind by slowing down that shift. I am scheduling a transmission replacement under warranty now at 70K miles.

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Jsolo

The upper gears should be easier because the rpm differences between are smaller. I recall reading that the lower gears have multiple syncro's vs the upper which only have one. This sheds light on why the upper gears can be a bit notchy.

The 1-3 is more a function of timing the clutch/rpm differences just right. Even when timed just right, 5-6 is just not as smooth as say 1-2 or 2-3.

The cold temp issue is the trans fluid. As I mentioned MT85 worked great initially then went to crap. The nissan fluid is not as smooth as MT85 but works year round (or so we shall see this winter). Pick your poison

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binary0x01

Funny 3->4, 4->5,5->6 are smoother for me than 1->2,2->3... 3rd gear is a biatch, sometimes nice sometimes not... fickle

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MagmaRed370z

I have had this small "grind" in 5th since the day I bought the Z with 3 miles on the ODO.

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Jsolo

Maybe I'm not describing things right. I'm referring to the feel in the shifter itself, as it engages the gear. In the upper gears, there's a bit of notchy feel in the shifter. The shift itself is still completed very smoothly.

I'm not overly concerned, the car will be under warranty for many years to come. If the trans starts to grind it'll get fixed.

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NismoNY

I'm interested in your reply. This might be the same thing I'm experiencing. Can you more clearly describe this occurrence? Does it happen all the time? Again, this feels like the shifter is scratching something or skimming something as it goes into 5th from 4th. It's not really audible the way a grind is but can be felt

Jsolo...the notchiness is normal. My 350z was nothing and so is this. Sometimes it feels like you're going thru a knot in the shift, right? Yep that's the notchiness and its normal