Gears Grinding Through Wot Changes

[No Crust Racing]

Hey guys, I've got a Series II 33, 5 Spd, and when I change gears from 3rd->4th or 4th->5th the box crunches into gear. This does not occur when shifting down, either normal down shift or double clutch, and only occurs going up through the gears and when I am changing gears under full load/rev conditions. When driving the car around normally the only issue is that the change from 1st->2nd is notchy/clunky/grabby if you get my meaning. Now the first problem to me seems like a worn clutch that's slipping when the engine is at full revs or worn synchros. The second issue definitely seems like a synchro issue.

Thoughts and ideas would be appreciated and if you happen to know the associated cost with your suggestion/idea/opinion, please include that info.

Thanks!

[Duncan]

Yep sounds like a synchro issue to me too...does it stop happening if you upshift more slowly?

If it happens stationery at idle its more likely to be a master or slave cylinder or clutch adjustment problem

[MerlinTheHapyPig]

you could try using redline gearbox oil. It's expensive, but has been known to solve a lot of these sorts of syncro crunching issues.

[No Crust Racing]

Nah, if I shift slower (IE allow revs to drop more) it doesn't crunch, which to me implied synchros. What kind of $$ are we talking for this redline oil? In addition, how does this oil solve crunching issues, I'm assuming it's a different viscosity to standard box oil?

Cheers

[MerlinTheHapyPig]

approx $120 for 3.7 litres

but well worth it imo.

[Bozz]

Just out of curiosity, if you're changing into 3rd, 4th and 5th at full throttle/rev points, what speeds are you doing and where?

[dezz]

approx $120 for 3.7 litres

but well worth it imo.

<{POST_SNAPBACK}>

how much is needed for a Series 2 R33 GTS-T?

[No Crust Racing]

how much is needed for a Series 2 R33 GTS-T?

<{POST_SNAPBACK}>

Yeah that's what I'd like to know, hopefully at 120 for 3.7L that'd be enough.

As for speeds, I change at between 6k-6.5K when I'm giving it stick and the change from 2nd to 3rd occurs at around 90-100 depending on ambient temp, gradient of road etc etc etc. 3rd goes to about 140 or so I think but I'm watching the road closely by this point. My car is speed limited so you only just get to shift into 5th and it's @ 180. Of the few times I've done this it's on a few very quite back roads late at night by myself.

so the question still remains... is 3.7L enough?

Any1 know what prices the Motul and Castrol oils go for?

[MerlinTheHapyPig]

approx 3 litres for rb25, 3.7 is definantly enough.

my rb20 box took 2.5 litres from memory.

motul and castrol probably cheaper, though do a search for "redline" on the forum, and you'll see how many skyline owners swear by it.

"liquid gold" mate!!!

[dezz]

approx 3 litres for rb25,  3.7 is definantly enough.

my rb20 box took 2.5 litres from memory.

motul and castrol probably cheaper,  though do a search for "redline" on the forum, and you'll see how many skyline owners swear by it.

"liquid gold" mate!!!

<{POST_SNAPBACK}>

and how often does it need to be changed? is it every 5000k's like the engine?

[MerlinTheHapyPig]

every 2 years / 50,000kms usually for gearbox oil

[dezz]

ah thats sweet. well worth using this redline stuff then

i was told every 10,000 for the gearbox, and 50,000 for diff

[IMACUL8]

The redline light wieght shock proof is excelent in the gear box - transformed my old wrx gearbox.

But no way I would leave it for 50000km. 10000 to 15000 max.

$120 for the large bottle is a good price.

[lwells]

If it happens stationery at idle its more likely to be a master or slave cylinder or clutch adjustment problem

<{POST_SNAPBACK}>

Duncan: by clutch adjustment, are you just talking the clutch pedal or is there some other adjustment in the hyrdaulic system?

[RANDY]

Tell me of this clutch-adjustment! =-p

[Ruffels]

yeah at high rev changes mine crunches into 4th

[jlnewton]

Redline is the ony gearbox oil to use. Although it does look rather funky My car was crunching 3rd to 4th almost regardless of speed. It would do it putting along at 60km/h. Changed the oil to Redline and it hasn't crunched since, even at track days. . . . .

[Duncan]

There is a threaded bar which the pedal uses to push the master cylinder, it can be lengthened or shortened if needed. But its not normally a problem, just an easy thing to try first

[RANDY]

Well... turns out that I have some other weird problem. The clutch slave was pushing on the little paddle when fully released, which meant that it was disengaging the clutch slightly the whole time. SteveGTS4 (mate) helped pull it out, then we grinded a bit of the pin of the slave off, and it pretty much doesn't slip anymore. I have a new slave on standby if anything goes pear-shaped.

The new slave's pin was longer, being new and all, and fitted worse than the old one. We're thinking that maybe something else was changed when a button-clutch may have been installed in Japan sometime?

[Rossman]

hey i reckon i need to get my hands on some redline gearbox oil...i saw $120 for 3.7L....wats the fluid capacity of the r33 gearbox? how much am i gonna need will 1 bottle do it?

thanks all

-Ross.