manual gear box oil

hey guys,
I've got a slight grinding noise comming from my gearbox that is only just noticeable. I can hear it when i'm sitting in neutral but when i put the clutch in it disappears. It can also be heard when driving in 2nd and 4th. My first thoughts are that the gearbox oil is the wrong weight, i have no idea what is in there at the moment, but what do you guys recommend using?

Thanks heaps

 

redline

redline shockproof i think it's called, very blue and very expensive, also very good

 

thrust or throw out bearing which ever you preferr

Sounds to me like a worn out thrust bearing or throw out bearing which ever you want to call it, it's inside the g-box bell housing its used the lift the pressure plate off.

usually makes a noise like that and goes away when you push on the pedal

 

Not sure what the cause is .....

but 2 bits of preventative insurance may help .... (might not fix the problem depending on what it is but will likely help. Also, these are common fixes experienced on a 15 yo 300ZX)

1. replace gearbox oil with Redllne lightweight shockproof - about $100. This gear oil is designed to extend the life of the gears in the gearbox and is beneficial to many 300zx manual gearboxes.
2. Replace the rear gearbox mount - about $150. (easy with a hoist).
Then:
3. Could be something else ....... centre bearing in the tailshaft etc.

Unless it's a clear vibration problem, I'd try 1 and/or 2 first.

Note: Thanks to Kyle (and myself), there's a tech article on a no mess method of refilling the gearbox.

Cheers,

Peter

 

I agree with ZWEET, sounds like thrust bearing.....

also, check your g/box shifter boots (there's 2 of them under the centre console) they come off sometimes and lift when selecting 2nd & 4th

It's amazing how much g/box noise you hear if the the top boot has come off the floor lip (it might even quieten your thrust bearing)

When you change your g/box oil, do yourself a favour and change the diff oil too (it might be 15yrs old )

 

I concur with a throwout bearing. The good thing about it is you can pretty much ignore it till the noise starts reaching levels to drive you mad!

 

Thanks heaps for the replies guys I'l get the gearbox oild changed and checkout all the other bits and pieces too.. need to replace the centre bearing aswell. Looks like i might need a couple of days and a spare 500 bucks!

Thanks again