Rb20 gearbox

[Jonnoo]

Hey guy another thread about gear oil

Every post i read turned into everyone saying each other is wrong with what oil to put in.

So it doesn't go into gear when cold unless i fight it

And it rarely crunches gear.

So reading the post everyone says use the following:

-Vmx-80

-Syntrans (i can only find syntrax?)

-redline shockproof (blue??)

Can i get a definitive answer please?

[GTSBoy]

Redline shockproof is somewhat of a bandaid solution to a gearbox that has sufficiently unhealthy synchros that they pretty much don't work.  Not the best solution, but compared to a complete rebuild, sometimes the best one available.  I used it in my RB25DET box after the transplant when it would not select any gear at all with the engine running (with conventional oil).  Instantly better.  Has been in there for years now, even though it has a reputation for not being the best thing to run long term.

Other gearbox oils are just gearbox oils.  Some a bit better than others.  Some offer the same rescue service that shockproof offers.  If your box refuses to engage gears when cold, I suspect your first port of call would be to try the best conventional oil and see if it helps, then be prepared to try the smurfs' blood.

[Jonnoo]

Thanks for the reply,
I think not selecting gears when cold may be low fluid or something,
So your saying i should try the vmx-80 or syntrans first

[KiwiRS4T]

Syntrax is the synthetic version so I would prefer that - or Motul Gear 300 75W 90 (and check that your clutch is fully disengaging).

[Jonnoo]

Syntrax $30p/L
Vmx-80&vmx-m $38 p/4L

Is syntrax really worth the money extra

[KiwiRS4T]

3 hours ago, Jonnoo said:

Syntrax $30p/L
Vmx-80&vmx-m $38 p/4L

Is syntrax really worth the money extra

Seems a small investment. What do you think you have in your box now that is different from the cheaper oil? I think you'll find Redline Shockproof is not cheap either.

[Jonnoo]

It wasn't about cheeping out, it was more about noticeable differences between the 'common oils' before i went with the redline.

Anyway its all done, i used syntrans

easy job, hardest part was getting the filler plug off.

Drained i recon just over 1.5 ltrs
Filthy oil had a bit of sludge
No big chunks of metal on the magnet

Filled about 2.4-2.5 L
Hopefully shes all good! If not its redline time!

[GTSBoy]

If it was ~1 litre short, then maybe you've found the cause.

[Jonnoo]

The 2 bottles above is how much came out

I used those 2 plus half a third, but i also spilt some.
No idea where a liter would have disappeared to tho

Gear changes do feel smoother
No abnormal crunches (not that there ever was) but definitely smoother...
I wont know for sure until tomorrow morning.

I think the clutch is disengaging properly, it doesn't roll when on a flat surface, next job is to bleed the clutch, never know when it was last done.

[Jonnoo]

Still a bitch when cold
Shifts are smooth when warm tho.

If i run through the gears when the car is off and then turn it on it will shift with a bit of resistance tho

[KiwiRS4T]

You should have used synthetic oil. I don't think shockproof is going to fix your problem. Have you got free pedal on the clutch?

[Hadouken]

Have heard of many cases where people have problems with car not going into gear when cold then they put smurfs blood in and vuala.

However. As mentioned before, it is a band-aid.

[Jonnoo]

You should have used synthetic oil. I don't think shockproof is going to fix your problem. Have you got free pedal on the clutch?

I used syntrans

[admS15]

Wack a tube of nulon smooth shift in it. About 15 bucks from supershit auto. Can't hurt but may help.

[Hadouken]

Should read up about full synthetic oils and what it does to synchros.

Everyone knows what redline does lol.

[Jonnoo]

Should read up about full synthetic oils and what it does to synchros.

Everyone knows what redline does lol.

What does it do?

Too slippery or something?

IDK man i think the box is just cooked lol

[KiwiRS4T]

2 hours ago, Jonnoo said:

 

I used syntrans

 

I know. I recommended Syntrax or Motul Gear but never mind. Do you in fact have any clutch pedal free play?

Anyway you may be right about the box. An RB20 box won't stand too much caning.

[Jonnoo]

I know. I recommended Syntrax or Motul Gear but never mind. Do you in fact have any clutch pedal free play?

Anyway you may be right about the box. An RB20 box won't stand too much caning.

Unfortunately they only had 1L in stock! I did try for the syntrax though.

Not really free pay but if i rev the car the peddle goes soft i can feel it sort of go lower if my foots resting on it, if that makes sense?!?

Yeah behind the 25 i don't think itll have much left even if it was fine

[KiwiRS4T]

Try bleeding the clutch anyway. Not familiar with your car but if possible adjust the clutch so that the pedal comes at least a little way off the floor before it begins to bite.

[Jonnoo]

Thanks for your help mate
Appreciate it, will definitely give it a crack on the weekend