Gearbox/Diff Oil & Brake Fluid Selection

[LuPix_S15]

To save people asking the same questions and for those wanting to deviate from the norm for more 'high performance' choices, I'm going to list what I'm changing to in terms of gearbox/diff oils and brake fluid etc

I don't want to start a 'which is better than the other' debate but this is what I will have running soon as I've got 100% trust in the person who has given me their advice based on knowledge and experience of using said products in similar environment (track & drift) :thumbs:

GEARBOX OIL
Redline Heavy ShockProof 75W-140
http://www.opieoils.co.uk/p-1023-redline-heavy-shockproof-gear-oil-75w-140.aspx

DIFF OIL
Fuchs Titan Race SYN 5 75W-90
http://www.opieoils.co.uk/p-68901-fuchs-titan-race-syn-5-75w-90-fully-synthetic-gear-oil.aspx

BRAKE FLUID
Motul RBF600
http://www.opieoils.co.uk/p-894-motul-rbf-600-factory-line-racing-brake-fluid.aspx


I'm gonna do the gearbox oil this week and the 'heavy' factor should help to preserve the gears a bit more and ShockProof will help with combating stresses from clutch kicking and launches etc. Believe gear changes will be 'stiffer' and more notchy when cold but I'm willing to accept this for better gear preservation when it's hot and being driven hard.

Diff oil I'll be swapping out the Redline Heavy currently in there for Titan SYN 5 fully synth as I reckon a slightly less sticky/viscous fluid will allow the diff to operate better within a drifting arena. Ever since I swapped for the Redline Heavy the diff has not felt right - it actually feels sluggish at times. It could be a problem with an older worn diff but I'm not convinced since she drifts well when going fast but when I need her to break traction at low speed it's not been the same as it used to be before the oil was swapped :wack:

Brake fluid wise - this will be done when I get the K-Sport calipers fitted but again the Motul has been recommended as way better compared against the Ferodo DOT 5 which I currently have and boiling points are apparently higher.

 

[andeep]

Spot on mate.

A lot of people recommend the Redline gearbox oil, and claims that it can save gearboxes.

 

[craig8585]

Redline do two versions of their shockproof oil - the lightweight and heavyweight. The lightweight oil is the one I use in the gearbox has the same actual viscosity as the Nissan MTF but acts the same as a lot thicker oil. It is really really good stuff and noticeably better than the normal MTF.

 

[LuPix_S15]

Yeah I can imagine the Nissan MTF is made and sold on the basis it's all nice and easy to use the box but when under more stress than shopping trips and a frisky drive I'm sure this is where Redline come into play


I'll report back on using the heavyweight for gearbox as my order has arrived and I plan on overfilling to help preserve and quieten the box a little lol...

I'm also gonna swap the diff oil as mentioned above from Redline heavyweight to Titan (Silkolene) SYN 5 - when I was talking to JameS15 today he also commented how the diff hasn't been the same since he swapped the oil for Redline heavyweight... it's just too thick in my opinion for drift work and seems to make diff lock up harder at slow speeds :wack:

 

[Toby]

What Quantities of each fluid did you require to do the change buddy? and I assume having ran this for a few months now you would agree it was an improvment?

 

[LuPix_S15]

Gearbox oil - buy 2 litres mate that should get it to just overflow.

Diff oil - again buy 2 litres and that'll definitely overflow by the time the second litre has gone 3/4 down

Brake fluid I'm not sure as I've yet to change this. They seem to sell all brake fluids in 500ml bottles so I'd suggest this should be enough. When the garage did my last change for me they gave me about 1/3 left over from 500ml bottle so I'm thinking this is more than enough :thumbs:


Done the box oil with Redline Heavy a few weeks back - is much better since it's slightly quieter and feels slicker when warmed up. A bit notchy as expected when cold cos it's much more viscous etc.

Literally just swapped diff oil with Titan SYN 5 today... all I can say is the Redline Heavy which was in there before is deffo NOT the right gear oil. It's too heavy and viscous. I reckon in hindsight it made the stock helical diff act more like an open diff at times - specially when hot and drifting! :wack: The difference can be felt mainly in the dry... Redline Heavy I could never get the wheels to lock and the backend out in the dry which was frustrating from drifting POV (this is on normal road surface and without clutch kicking). But now I've swapped for SYN 5 I've driven the same roads in the dry today and the backend comes out real good. The diff feels alive again, sideways action is smooth and much more progressive. It's only my opinion but I'd never recommend the Redline Heavy as diff oil ever lol... Even SXOC and Opie Oils say Titan SYN 5 is the top choice for S15 stock diffs

 

[craig8585]

A few of including myself run the redline heavyweight diff oil for some time. Personally I've not had any problems with it and I notice the wheels locking quite easily at low speeds and even low power on tight turns.

I've not tried the Titan SYN 5 myself so can't comment on this oil but as I have had no problems with the redline it will be staying.

 

[Toby]

I suppose alot depends on the state of you're diff, if its still in reasonable nick you can get away with a less viscous oil!

Cheers for the input!

 

[craig8585]

That would be the normal train of thought but James is saying the less viscous oil allows his diff to lock easier.. Who knows!

 

[andeep]

Might have to try some of this Titan stuff! Or I could stop spending money and get a 2-way...

 

[TurboAL]

I put the amsoil 75 - 90w servere gear oil in my box after reading a through indipedent scientific study proved it was the best up against a whole host of the well know brands.

Brake fluid spot on DOT 4, I was recommeded this by someone who has a lot of track experience.

 

[craig8585]

Yeah, that dot 4 Motul RBF 600 that James posted is really really good stuff and better than the dot 5.1 fluids contrary to popular belief.

 

[LuPix_S15]

Craig lol forgot to speak to you about this today! :wack:


Yeah I really do find the Titan SYN 5 allowing me to lock and generally feel of the diff is so much smoother and better... I'm 100% sure I'm not imagining it haha I've had the Redline in car for at least 7/8 months and being a daily car I'm used to how she is with Redline but SYN 5 suddently makes her feel so much better IMO :thumbs:

I guess it could all be down to how worn my diff is - maybe this has a bearing. Maybe it's locking ability is now severly hampered by gear oil that's too viscous?!

So I reckon both types of diff oil has it's own set of supporters hehe

 

[craig8585]

When I drop my subframe I'll have to replace the diff fluid so may try the Titan to see if it feels any different. Unless I've got the Redline in stock already!!

 

[LuPix_S15]

Cool... would be good to have a second opinion but the SYN 5 was recommended by someone who I very much trust his judgment. He own's an S14a and also when I called to order it, Opie also said to me this was their recommended diff oil for the S14/15 as well

 

[Benne]

It´s hard to get Redline Oils here in Germany so I´m using Motul Gear FF (Le Mans approved) in gearbox and diff, it´s also 75W140 and works quiet well!

 

[Fruitbooter]

Great write up James :nod:

Can you just add the correct places to fill them up from?

Gearbox - Did you do it inside car by removing gear surround? Or did you remove one of the plugs and go from under the car?

Diff - Remove rear wheel and use pipe?

 

[LuPix_S15]

Jay - the following guide thread I put up shows where the box oil filler and drain plugs are:

http://forum.s15oc.com/showthread.php?7509-Gearbox-Oil-Change-Guide

Also the method I used involves getting the garden hose pipe fed through the centre console with everything removed etc and feeding this down to the box fill point...


The diff drain is dead easy - at the bottom of the backplate. But before you undo this and drain the diff oil make sure you can get access to the filler plug which is around the back of the diff but higher up. You'll deffo see it easy Also you'll need a drain plug adaptor (square shaped head) to remove. For the diff a 13mm adaptor is spot on... 1/2" is near enough so you can use the end of a breaker bar but you won't be able to get a breaker bar to the filler plug - it's too big and the exhaust pipe gets in the way lol. So just get a drain adaptor tool :wack:

Yep once you've drained or waiting for it to drain out of the diff, remove the passenger side rear wheel and feed a garden hose into the filler point. Then stick a funnel on the end and pour in 2 litres of diff oil :thumbs:

 

[Topper]

I remember reading a thread re the Redline stuff being a bit to harsh for the gearbox, may have been the heavy rather than the lightweight stuff.....

 

[sliding-r]

I read that also, like it masks the problem whilst not being as protective... Sure it wee a American forum..

Anyway James I may have to try swapping over the diff oil as I'm struggling with low speed openwheeling when try to spin round..

Higher speed drift seems ok for mine..