Busted New 30A Transmission (Whining Like Straight Cut) - Surely Not

[GoHashiriya]

Hi all, just got back from the track today, after the last run I noticed a whining noise at idle, like straight cut gears but not quite so high pitch. It's pretty loud. With my foot on the clutch there is no noise and there is no noise on deceleration. I noticed it would get louder and higher pitch with engine speed until the point where engine noise drowns it out.

The gearbox (30A) was installed a few thousand kms ago, it's had one oil change. I used a second-hand Nismo clutch/ lightweight flywheel kit in the install, the condition was average on installation with the clutch approximately more than half-worn. The lightweight flywheel seems to rattle a bit more as of today but maybe I'm imagining it.

I would normally associate this with input shaft bearing noise, from reading other noise-related gearbox threads. But surely not, not after this amount of time? The car is going to the shop in a week for some brake work so I will ask for my mechanic's opinion then; going in with some other opinions would be helpful.  

[r32-25t]

Is there oil in it 

[GoHashiriya]

I changed the oil not so long ago and there’s been no indication of any leaks. I was under the car on Saturday and it was clean so unless it came out over the last couple of days, clung entirely to the underbody and didn’t give off any smell. I’m gonna say (pray) it’s still in there. 

[r32-25t]

First thing I would do it drain the oil and see what it looks like. 

[admS15]

I had a similar issue with a new box after 1 track day. When I drained the oil, it told the story. Let's just say it glittered like gold.

Im not sure exactly what went wrong as I didn't have it pulled apart as the nice chaps at Nissan where nice enough to replace it with another new one. Thank you Mr Nissan, I bow down to you.

 

I'm assuming it was a broken/stripped synchro. It was still selecting and had drive in all gears but was making a whine noise. At first I thought it was a bad turbo bearing but then realised the noise went away when stepping on the clutch pedal. From memory I think the whine got quieter in 4th gear.

 

Sounds very similar to what you're describing, hopefully not.

[GoHashiriya]

On 11/30/2021 at 2:06 AM, r32-25t said:

First thing I would do it drain the oil and see what it looks like. 

On 11/30/2021 at 5:51 AM, admS15 said:

I had a similar issue with a new box after 1 track day. When I drained the oil, it told the story. Let's just say it glittered like gold...

I'll take the oil out next Monday and have a look - fingers crossed. 

Anybody have any experience with Nengun refunds/exchanges?  

 

[admS15]

Don't assume the worse yet. Could be as simple as a dodgy thrust bearing. The oil is your fortune teller and should give you a direction to follow.

[Dose Pipe Sutututu]

Or could be someone put in the thrust bearing in backwards and now it's stuffed, although a cheap part to replace the labour cost more.

Dump oil first, then next box off inspect thrust / throwout bearing whatever it's called these days 

[GoHashiriya]

Cheers guys. I’ll mention this to my mechanic on Monday, luckily he performed the work which helps in the way of warranties - hopefully. 
 

I’m at the very least annoyed about the US$100 cost of the oil but given that pales in comparison to the cost of a new gbox, I’d be relieved if this doesn’t cost me another US$2k.

I’ll update with our findings. I’ll also get a video clip for others to use as a sound reference. 

[GoHashiriya]

Here's a video I took to capture the noise. I am engaging/disengaging the clutch in the video, also attempting to do it slowly to hear the change in pitch when the transmission begins rotating. It doesn't sound promising.

 

 

[Dose Pipe Sutututu]

Should wind back your odometer so when you deregister, it has low kms on it.

You know us Australians froth over low KMs, even if it means nothing at all.

[GoHashiriya]

On 12/3/2021 at 9:26 AM, Dose Pipe Sutututu said:

Should wind back your odometer so when you deregister, it has low kms on it.

You know us Australians froth over low KMs, even if it means nothing at all.

Hahaha, I like ‘em high, another deterrent for the thieves over here.

[GoHashiriya]

Hi all,

Took the car in to the shop to diagnose the gearbox noise. The mechanic was pretty sure it was the gearbox from the off, although he said the noise was much louder from the bellhousing and noted the possibility of it being the release bearing. He took the box out, tried a new release bearing to no avail, drained the oil - which looked incredibly metallic - and stated it's the box. Which is pretty much all there is to it - further opinions welcome.

I took pictures and we made a video documenting our findings - yeah that tray was clean before.

 Video: 

 

Edited December 13, 2021 by GoHashiriya

[r32-25t]

That oil looks pretty thin, bet they used synthetic oil which these gearboxes absolutely hate 

[GoHashiriya]

I had to keep this quiet as it's been a long-winded battle of blame between myself/my mechanic and Nengun/Nissan. But in short, I was refunded for this box. I have placed an order for a new one - prices have gone up 20% since June and there's a 3-month wait. In the meantime I'll be using this box, hopefully drive a few more events on it then swap it out in March/April.

I appreciate all your opinions, it helped when talking with my mechanic. I would love to determine what has gone wrong  but I'm not expecting it to be determined quickly.

On 12/14/2021 at 8:57 AM, r32-25t said:

That oil looks pretty thin, bet they used synthetic oil which these gearboxes absolutely hate 

The OEM stuff was swapped out at about 800kms with Castrol Syntrans (TAF-X) 75w-90 GL4+, pretty sure it's fully synthetic. During the recent diagnosis I swapped it back to Nissan GL4 75w-85.

You're right, it looks like p*ss. 

[Dose Pipe Sutututu]

Samsonas or BMW DCT or ZF8HP 

no more gearbox issues.

[joshuaho96]

On 12/20/2021 at 5:53 PM, GoHashiriya said:

I had to keep this quiet as it's been a long-winded battle of blame between myself/my mechanic and Nengun/Nissan. But in short, I was refunded for this box. I have placed an order for a new one - prices have gone up 20% since June and there's a 3-month wait. In the meantime I'll be using this box, hopefully drive a few more events on it then swap it out in March/April.

I appreciate all your opinions, it helped when talking with my mechanic. I would love to determine what has gone wrong  but I'm not expecting it to be determined quickly.

The OEM stuff was swapped out at about 800kms with Castrol Syntrans (TAF-X) 75w-90 GL4+, pretty sure it's fully synthetic. During the recent diagnosis I swapped it back to Nissan GL4 75w-85.

You're right, it looks like p*ss. 

I'm surprised you got a refund. I would have figured that between the gearbox being sent overseas and your mechanic likely not working for a Nissan dealer they would've told you to pound sand.

[GoHashiriya]

On 12/21/2021 at 11:34 AM, Dose Pipe Sutututu said:

Samsonas or BMW DCT or ZF8HP 

no more gearbox issues.

The costs are certainly heading in that direction. Hell, I already commited to financial ruin by buying a Skyline in the first place.

On 12/21/2021 at 1:24 PM, joshuaho96 said:

I'm surprised you got a refund. I would have figured that between the gearbox being sent overseas and your mechanic likely not working for a Nissan dealer they would've told you to pound sand.

Perhaps it was a different story as I am based in Japan. I agree with the latter remark about my mechanic not being a Nissan dealer though. 

[admS15]

Great result and Nissan/Nengun was pretty speedy with the refund. My saga dragged on for 9+ months before a replacement landed on my doorstep.

Surprised they're letting you keep it.

 

[GoHashiriya]

On 12/21/2021 at 3:57 PM, admS15 said:

Great result and Nissan/Nengun was pretty speedy with the refund. My saga dragged on for 9+ months before a replacement landed on my doorstep.

Surprised they're letting you keep it.

 

I was expecting the same. The box was on the floor at my mechanic’s and everyone was getting annoyed. I figured there’d be no resolve, ordered a new transmission, and put the noisy box back in. When factoring-in what I sold the old 71c for I’m about even, there’s a slight loss when considering the new transmission. 
 

If I ever figure out what caused this I’ll update this thread.