Haptic

iTrader: (2)

So my gears have been grinding recently. I got the car at 85k and it is now at 87k, and ever since i got it 6th gear has grinded sometimes when i go into , usually when i go into gear quickly. 6th gear isnt a big deal for me but now my 3rd gear is grinding and its much worse than 6th which greatly concerns me. Like 6th gear it usually grinds when i shift quickly as opposed to slowly. I did some reading and it really seemed like the snychros are going bad which we all know is a side effect of the poorly made transmissions in the 03 Z's. However i took it to the head mechanic at the car dealership where i work and he looked at it and said that he thinks its my throw out bearing because my car has a spinning/whining noise when in idle with the clutch up. I thought that was a different thing entirely but i honestly dont know , im not a professional mechanic. I just wanted to get some helpful imput from the community here since i know some of you are avid car mechanics. Thanks.

binder

iTrader: (8)

First, I wouldn't go back to that mechanic because while the clutch pedal is up (clutch disengaged) the throw out bearing is no longer touching the pressure plate therefore it is unloaded and won't make noise. Throw out bearings that are failing make noise when you press the clutch and load the bearing.

The throw out bearing has nothing to do with the shifting though. They do frequently wear out so I wouldn't doubt that it might be going bad but the mechanic doesn't know what he is talking about if he said it makes noise with the clutch disengaged.

The oem transmission does have synchro failures most commonly at 3rd and 5th but it could happen on any gear. The reason it happens when you shift fast is because the synchro isn't able to react fast enough. Your options are to replace the transmission with a cd009 (revised synchros) or just work the gears slower (double clutch it).

CD009 can be purchased used on the forums here for under 1000$. I would resurface the flywheel and pressure plate and put a new friction plate in the clutch along with a new throwout bearing while you have the transmission out as well.

oldschool350z

iTrader: (1)

Bad synchros. .

normally you're better off getting a new or used tranny because you need special tools for the transmission and it's quite complicated. Most shops charge $200 or more just to drop the transmission.

you can switch to Redline MT-90 and prolong the life of the trans. My celica has 4 gear grind there for over 6 years and still going.

And what binder said is all true. Mind as well do something to the clutch and flywheel since the transmission is out. A lot of people simply upgrade to a higher performance or JWT. I personally like to stay stock but that's me.

binder

iTrader: (8)

MT 90 is going to be too heavy for these transmissions. OEM is 75 although being in florida he might not have issues with mt 90. It is harder to get into gear with thicker oil so it might exacerbate the problem.

Haptic

iTrader: (2)

Thanks for the imput guys, i was pretty sure it was the synchros as well but im not a mechanic. And ya that's exactly what i was planning on doing: replacing the transmission with a CD009 and selling my old one for whatever i can get. Im going to tell him that im almost positive its the transmission and ask if he can swap it with my old one. Additionally, does anybody have any clue what is causing the spinning/whining sound with the clutch disengaged?

oldschool350z

iTrader: (1)

Ah yes I'm not too familar with the 350z and what it call for. But chaning the transmission oil could help until you can afford a different tranny. You can sell yours for parts and someone who has the skills might fix it up.

May I ask if that happened when you test drove the car before you bought it? If not could be the seller was hiding it.

That sound you hear could be the throw out bearing which is common on any z. doesnt do any damage to my knowledge just loud and annoying. But the grinding is synchros and that needs to be replaced. You could lose whatever gear such as 3rd or 6th as you say you have issues with.

But hey at least you got a Z and you know what it needs. A lot of people buy a car without getting it checked out by a mechanic and things like this happen.

Haptic

iTrader: (2)

I test drove it but i had to pick it up about 200 miles from where i live and the 6th gear grind is very trivial in terms of its grinding as i can just enter 6th slowly and almost always prevent grinding. But 3rd is a very commonly used gear and it grinds probably twice as bad as 6th, 3rd gear didnt start grinding until a couple days ago. Its possible the guy knew, he was pretty shady but all in all its in pretty good shape. Thanks for the info, i was pretty sure the noise was unrelated to the grinding. I think im just going to find a used CD009 tranny with low miles and swap it for mine and i shouldnt have anymore problems with it. And in a way im excited because people say the shifting is loads better on the CD009. Oh and i did also hear that changing the transmission oil with oem oil would alleviate the issue temporarily. Thanks for the help.

oldschool350z

iTrader: (1)

No problems thats why were here. And yeah I would say it if was only 6th gear grinding just keep the tranny but 3rd is something you need for daily driving.

As since you'll have the transmission out I would change the clutch and flywheel. It would need replacing at some point.

Brand new 350z transmission

Chadro

JWT Clutch/Flywheel combo is the way to go. I love it.

oldschool350z

iTrader: (1)

Part number ? i know there are two different setups

Chadro

http://www.conceptzperformance.com/C...134.67.231.249

oldschool350z

iTrader: (1)

Damn it's so expensive lol. But good quality and all parts for the 350Z are pricey.

binder

iTrader: (8)

Disengaged (pedal up) the noise could be the clutch friction disk rattling around since there is no pressure on it from the pressure plate. If the noise goes away when you depress the clutch pedal then that is the case. If it gets worse then it's probably the throw out bearing because throw out bearings that are bad increase noise when loaded against the pressure plate.

My cd009 shifts about the same as my previous but just no grind in 3rd.

If it will be a while before you get it changed just double clutch. Go from second to neutral, let the clutch out, rev the engine to the proper rpm, depress clutch and then select third. That's basically what a synchro does at a very fast rate. Grain trucks on the farm didn't have sychros so I had to learn the old hard way. Also a duece and a half in the army has shitty transmissions so I double clutched to help make those drive easier.