5th gear scratch (not a grind)
 

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!

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.

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.

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.

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.

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.

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

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).

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

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.

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 :)

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

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

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.

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

Taking the car to the dealer this weekend just to confirm the issue. If it's nothing or normal then that's fine with me. At least the car is CPO till 2021

uhh our first is super short and going from 1-2 i'd be pausing to let the rev's drop enough to smooth the transition.

i did swap my trans/differential fluids 1000km ago and noticed the shifts being smoother again. marginally at best. can't tell the differential, guess i'm not driving around corners fast enough :icon17:


if you're having trouble with your upper gears i'd def get your synchro's checked. i have no problems 3-4, 4-5, 5-6 and going rowing back down. always have difficulty engaging 1st from a rolling stop when cold and 3-2 shift when very cold. i generally don't rev about 3k until i see the coolant temp move up to operating temps.

It does not happen all the time. Maybe 5% of the time. Going from 4th to 5th I can feel a little bit of a metallic sound similar to a very small grind.

Perhaps this is what we are feeling. Taking it to the dealer tomorrow but with my luck, they won't be able to replicate it since it happens rarely.

I had the syncro (grind) issue in both 5th and 6th. Most of the time it would happen when I would change gears involving a large rpm range change (i.e. 3rd-to-5th or 4th-to-6th). Took it to the dealer and they replaced the tranny under warranty. Haven't had an issue with the new tranny but it only has 5-6k miles on it (although at least 5k of those miles are boosted miles with around 550ft-lbs at the crank).

Just make sure you explain the exact conditions it happens. I had to talk directly to the tech and tell him when I experience it. He drove it around the block and immediately came back and said they were replacing the tranny.

Mine does this in 5th every single time when cold. Going from 4-5 or down from 6-5. Then when the car warms up a bit it stops completely.

i have the same issue, so when its cold I always go to neutral before switching to the next gear solves the problem for some reason.

My car has done the same thing since about 23k (now have 65k)

I have worked around getting the transmission done by just letting the car warm up before I really start shifting hard from 4th to 5th.

It seems it only "scratches" when the oil temp is low and the fluid is more viscous in the transmission...

:iagree:

I had this issue with only 10k on the car. only shifting to 3rd.. Changed the fluid and now it is gone. I am at 23k

Nissan told me to go suck an egg when I asked for transmission replacement under warranty a few years back. Over 100K miles now and no change. It seems in my experience the scratch is most noticeable with a quicker shift (4-5) on a cold transmission at lower RPMs. I've also found that a slower shift or double clutch with proper rev match pretty much eliminates any noise regardless of the temps or speed.

Infiniti replaced mine and they couldn’t even duplicate it on a test drive. Service Manager said they had a write up from the manufacturer about it so he’d go ahead and replace it for me. It’s funny how much better service you get from a ‘luxury’ dealer.

I took them on a test drive to demonstrate exactly what the problem was. What irritated me the most was the warranty wasn't even through Nissan. It was a 3rd party - so I'm like if you guys just approve the damn thing, someone else will pay you to install it. No dice :shakes head: