gearbox

[ratty_ratty]

got a problem with me box

when i go from 4th to 5th it grinds like no tomorrow

but if i was to put it from 4th to 5th slow and try to get the stick close to the left of 5th gear i can it is fine

is it time i need a box or does something need adjusting

and if i need box any ides how much roughly i can get one for

thanks people

[SiH]

Mine does this too I had a 200sx before though, so i\'m used to it

Think it may be the synchro\'s.
Going to try changing the box oil and see if that helps

[ratty_ratty]

ok thanks buddy i will try this as well

[Bobbit]

It\'s the syncro, it\'s a common fault going from 4th to 5th, new oil does help, if you use thicker oil it really can help but takes longer to warm up.

[Andy_k]

Yeah syncro as others above have said, have a look on rx7club.com they use some good fluids that help.
In the long run though it will need rebuilding/replacing.

[feelio]

Mine does it too......syncro!

If you double clutch it won\'t grind!

I found this web site, have a look at how to change the syncro. I haven\'t read it through thoroughly so you will have to see for yourself if it\'s useful. Hope it helps.

http://www.3rdgenrx7.com/

[SiH]

Surely double declutching won\'t really help going up through the gears?
Mines worst when skipping 4th (yeah, i know, i shouldn\'t...) - i.e. blast in 3rd then knock it into 5th to cruise on the motorway.

[feelio]

Surely double declutching won\'t really help going up through the gears?

Works for me.....you\'ll have to try it! It just stops the annoying noise when you change from 4th to 5th!
I think it matches the gearbox to the engine revs. Not sure how it works, maybe someone else will confirm and explain.

[rx7boy]

I have the same on mine, have been told by a gearbox specialist that if you take ur time moving from 4th to 5th then u will get less of crunch, i have tried this and have had some success but everyso often it still goes. Bobbit your right thicker oil really does make a difference but eventually you will nead to rebuild, to rebuild the gearbox it will cost you about £600 excluding any new parts that are needed, does come with 1 year warenty but u have to be without ur gearbox for upto 4 weeks.

[Nik da Greek]

My last FD did this, had it for two years and it never got any worse. It was always on my to do list, but fortunately I wrote the car off before it became a pressing issue. Alls it means when the synchro goes is that it\'s not matching the speeds of the two cogs together properly, so they graunch a bit whilst one forces the other to spin at an identical speed, which is why double declutching in theory allows them to have a bit of a pause and find their own speed together cos the drive load is off them.
 
Did that make sense? I\'ve just had one of those "I\'ve read back my own post and it sounded like gibberish to me, how\'s anyone else got a chance" sort of moments

[Ricco_04]

Would it be syncros if its difficult to go from 1st to 2nd or just crappy oil?

[Nik da Greek]

Synchros are usually accompanied by a very distinctive graunch, like when you go into reverse and the cars\' not quite stationary. In theory, they can go between any gears, but the change to fifth is most common. I think second to third is prone to it, too. If your first to second is just really stiff and doesn\'t grind, it could well be something else, the synchro going doesn\'t really make the change any harder, it just makes a nasty noise. Mine\'s a pig to get into second until it\'s all warmed up then it\'s fine. Could be a problem with clutch engagement or bleeding, maybe?

[Ricco_04]

Ah I see.  Thank you for that :Thumbs-up

Mine does get better once oil has warmed up.  Guess a good gear oil change and also clutch/brake fluid change should sort that out.  As you have described then my syncros sound ok

Dam that reminds me, I need an uprated clutch!

[ratty_ratty]

what is the best gear oil to use??

[David Nock (RIP)]

FB loves 75W 90 full synthetic gear oil. Castrol/Valvoline etc.
I think the FD is the same - check book. The important thing is full synthetic - it gives a smoother drive altogether.